BANCROFT 
LIBRARY 


THE  LIBRARY 

OF 

THE  UNIVERSITY 
OF  CALIFORNIA 


THE-  ORES  OF   Li:  ILLE 


MORNING          EVENING  STAR  M 


METHODS   OF   THEIR  EXT       >     •      s 


LOUIS    D.    RICKETT- 

Ward  Fellow  in  Economic  •' 


THE   ORES  OF   LEADVILLE 


AND 


THEIR  MODES  OF  OCCURRENCE 


AS  ILLUSTRATED   IN   THE 


MORNING  AND  EVENING  STAR  MINES, 


WITH   A   CHAPTER   ON    THE 


METHODS  OF  THEIR  EXTRACTION  AS  PRACTICED 
AT  THOSE  MINES, 


BY 

LOUIS    D.    RICKETTS,   B.S. 

fc—  s 

Ward  Fellow  in  Economic  Geology  of  the  College  of  New  Jersey. 

WITH  FIVE  PLATES  AND  ONE  COLORED  LITHOGRAPH. 


PRINCETON,  1883. 


*f 

ibr 


ft  Library 


PREFACE. 


In  accordance  with  the  requirements  of  the  W.  S.  Ward  fellowship  in  Eco- 
nomic Geology  for  the  year  1882-3,  I  spent  over  four  months  of  that  year  at  Lead- 
ville,  and  devoted  my  time  to  a  study  of  the  ores  and  their  modes  of  occurrence, 
and  to  the  extraction  of  ores  in  the  Evening  and  Morning  Star  mines. 

To  these  mines  I  had  free  access,  and  would  here  tender  my  thanks  to  their 
officers,  who  afforded  me  every  facility  in  their  power  for  the  prosecution  of  my 
work.  The  analyses  of  the  rocks  and  ores  were  made  and  the  thesis  completed 
at  the  School  of  Science,  Princeton,  during  the  remainder  of  the  college  year. 

I  have  been  greatly  stimulated  throughout  by  the  personal  interest  taken  by 
Mr.  Ward  in  the  work ;  and  it  is  at  his  request  and  expense  that  this  thesis,  writ- 
ten in  compliance  with  the  terms  of  the  fellowship,  is  published. 

Part  First  is  also  presented  as  a  thesis  for  the  degree  of  Doctor  of  Science. 

L.  D.  RICKETTS. 

PRINCETON,  N.  J. 

June,  1883. 


PART    FIRST. 


THESIS    FOR  THE   DEGREE  OF   DOCTOR   OF   SCIENCE. 


INTRODUCTORY. 


This  thesis  does  not  so  much  attempt  a  general  description  of  all  the  mines 
of  Leadville  as  a  more  particular  description  of  the  mines  to  which  the  writer  has 
had  free  access  for  several  months.  And  it  is  hoped  by  a  more  detailed  descrip- 
tion of  these  quite  extensive  mines  to  give  a  better  idea  of  this  type  of  deposit 
than  could  be  done  by  a  more  superficial  description  of  a  greater  number  of 
mines.  Other  mines,  both  on  Carbonate  and  Iron  Hill,  have  been  visited  in 
order  that  common  features  may  be  noted  and  peculiarities  distinguished,  but 
almost  all  the  data  for  the  following  pages  have  been  derived  from  the  MORNING 
and  EVENING  STAR  MINES. 

The  Morning  Star  especially  has  been  studied,  for  this  mine  is  only  at  pres- 
ent undergoing  development,  and  large  bodies .  of  ore  stand  open,  completely 
explored  by  drifts  but  otherwise  untouched,"thus  affording  most  excellent  oppor- 
tunities of  examination. 

The  Evening  Star,  on  the  other  hand,  is  much  smaller,  and  the  ground  devel- 
oped is  practically  'exhausted.  Its  enormous  ore-body  has  been  removed,  and 
only  lofty  cribbing  and  timbers,  reaching  up  set  over  set,  show  the  great 
spaces  once  occupied  by  almost  pure  ore.  The  present  shipments  (October  and 
November,  1882)  are  obtained  from  the  smaller  ramifications  of  the  ore  through 
the  gangue,  and  the  apparently  interminable  number  of  these  smaller  bodies 
promises  to  be  the  source  of  much  more  ore.  Further  prospecting  work  is  now 
being  pushed  forward,  through  which  it  is  by  no  means  impossible  that  new 
ore-bodies  may  be  struck.  It  would  be  truly  rash  to  assert  that  the  Evening  Star 
mine  is  nearly  exhausted  without  adding  the  qualifying  clause,  if  new  ore-bodies 
are  not  presently  developed. 

The  excellent  report  of  Emmons,  an  abstract  from  his  final  report  on  the 
geology  and  mining  industry  of  Leadville,  has  been  of  the  greatest  assistance  to 
the  writer,  and  is  used  as  an  authority  in  the  short  description  of  the  general 
geology  deemed  necessary  for  an  intelligent  comprehension  of  the  subject  treated. 
For  a  fuller  description  of  the  general  geology  that  pamphlet  is  referred  to,  as 


8  INTRODUCTORY. 

space  for  this  is  lacking  here.  The  statements  of  Emmons  concerning  the  strata 
and  their  nature  at  different  horizons  have  corresponded  very  well  to  the  facts 
gathered  in  the  limited  field  here  treated.  As  will  be  mentioned  later,  the  posi- 
tion of  the  Carbonate  fault  is  found  to  be  further  down  the  hill  than  it  is  stated 
to  be  by  that  authority,  and  indeed  no  direct  evidence  of  its  existence  could  be 
obtained  on  the  property.  These  and  a  few  other  points  of  minor  importance 
rendered  apparent  by  the  developments  lately  made  on  the  lower  part  of  the 
properties  disagree  with  his  statements.  All  the  others  correspond  very  nearly. 


GENERAL    GEOLOGY    OF    THE    DIS- 
TRICT. 


The  stratified  rocks  about  Leadville  are  almost  altogether  Palaeozoic,  with  an 
immense  amount  of  Quaternary  debris  on  the  lower  slopes  of  the  hills,  and  run- 
ning into  and  over  the  broad  valley  of  the  Arkansas.  Between  certain  of  these 
stratified  Palaeozoic  beds  are  found  a  complicated  series  of  interlaminated  intru- 
sive sheets  of  the  igneous  rocks  so  intimately  connected  with  the  ore-deposits. 
The  upper  part  of  the  Mosquito  Range  and  of  the  opposite  Sawatch  Range  is. 
composed  of  Archaean  rocks,  principally  granites  and  gneisses.  These  are  of  dull 
colors,  for  the  most  part  gray  and  pinkish.  Gneisses  predominate,  and  in  these 
a  distinct  bedding  is  often  recognizable.  They  split  up  and  disintegrate  along 
these  lines  as  well  as  along  the  jointing  planes.  Frequently,  along  the  Sawatch 
Range  at  least,  they  are  intersected  by  dikes  of  igneous  rock  which  weather  to 
thin  plates  and  blacken  and  form  prominent  stripes  of  slide  down  the  mountain- 
side wherever  they  occur. 

The  sedimentary  beds  form  a  belt  around  the  base  of  these  mountains  and 
extend  well  up  on  their  sides.  About  the  granitic  rocks  and  immediately  above 
them  there  is  a  bed  of  quartzites  of  the  Lower  Silurian  age.  It  has  an  average 
thickness  of  about  1 50  feet.  This  sheet  is  not  homogeneous,  but  consists  of  nume- 
rous layers  of  quartzite,  some  shales  and  some  calcareous  rock.  The  lower  half 
is  by  far  the  more  pure.  Conformably  upon  these  there  follows  a  bed  of  impure 
siliceous  dolomite,  and  then,  ending  the  Silurian  formation,  a  thin  though  gener- 
ally persistent  stratum  of  quartzite.  This  stratum  is  both  thin  and  irregular.  Its 
thickness  varies  from  10  to  40  feet.  Emmons  thinks  this  irregularity  in  thickness 
may  be  due  to  erosion,  especially  as  he  was  unable  to  find  any  Devonian  formation 
at  this  point.  This  stratum  was  the  only  one  not  identified  on  either  the  Morning 
or  Evening  Star,  and,  as  the  White  limestone  was  found  to  be  much  thinner  here 
than  the  average,  erosion  may  have  removed  all  of  the  quartzite  and  a  part  of 
the  limestone  at  this  place. 

The  Carboniferous  strata  are  the  most  important,  as  it  is  in  these  that  all  the 
ore  of  Carbonate  Hill  and  almost  all  that  of  the  rest  of  Leadville  is  found.  They 
consist  first  of  a  layer  of  blue  dolomite,  very  pure  when  unaltered,  but  in  the 


10  OCCURRENCE   OF   THE  ORES. 

neighborhood  of  the  deposits  very  much  stained  and  changed.  This  is  the  stra- 
tum in  which  the  ore  occurs.  The  rest  of  the  beds  of  this  formation  form  a  series 
of  coarse  grits  and  sandstones,  with  a  few  narrow  layers  of  dolomite.  When 
least  eroded  they  are  2500  feet  thick,  but  in  the  vicinity  of  the  deposits  now 
worked  they  have  been  almost  entirely  washed  away. 

Although  places  have  been  found  where  the  various  sedimentary  formations 
succeed  each  other  without  interruption,  such  occurrences  are  extremely  rare. 
There  is  scarcely  a  spot  where,"  at  some  horizon,  igneous  rocks  have  not 
forced  themselves  in  between  the  strata.  These  igneous  rocks  are  acidic.  They 
are  regular  quartz-porphyries  or  felsites,  and  are  called  by  Emmons,  and  generally 
throughout  the  camp,  porphyries,  and  that  is  the  name  that  will  be  given  them 
here.  Many  varieties  may  be  recognized.  White  and  Gray  porphyry,  of  which 
more  hereafter,  are  the  varieties  most  intimately  connected  with  the  ore.  These 
rocks  are,  comparatively  speaking,  seldom  found  in  ordinary  dikes,  but  occur 
for  the  most  part  as  intrusive  sheets,  following  the  bedding  of  the  formations  in 
which  they  occur.  Regular  overflows  are  never  found,  and  if  they  had  once  ex- 
isted erosion  would  long  ago  have  removed  them.  The  most  important  sheets 
of  porphyry  occur  above  the  Blue  limestone,  or  in  it.  The  larger  occur  above  it. 
In  thickness  they  average  about  the  same  as  the  Blue  limestone,  though  in  some 
cases  they  are  much  thicker,  and  on  Carbonate  Hill  the  White  porphyry  almost 
certainly  attains  a  thickness  of  1000  feet. 

Besides  this  great  complication,  due  to  the  intrusive  masses  of  porphyry,  the 
geology  of  the  district  has  been  rendered  additionally  complex  by  a  series  of 
faults  which  break  the  continuity  of  the  beds.  That  these  were  made  after  the 
eruption  of  the  porphyries  is  proved  by  the  latter  being  broken  too.  Like  evi- 
dence proves  that  the  faults  occurred  subsequent  to  the  deposition  of  the  mineral 
matter.  In  direction  the  principal  of  these  faults  have  a  trend  north  and  south, 
parallel  to  the  mountain-range,  though  numerous  minor  faults  run  off  from  these 
at  various  angles.  There  are  five  or  six  of  the  larger  ones.  The  western  wall  has 
fallen  on  all  but  one  of  them.  Only  two  of  these  faults  have  any  connection  with 
Carbonate  Hill ;  the  Carbonate  fault,  running  along  the  western  slope  of  the  hill, 
and  the  Iron  fault,  far  to  the  east  and  dividing  Carbonate  from  Iron  Hill.  The 
deposits  were  first  discovered  on  the  exposures  made  by  erosion  along  these 
faults  or  the  anticlinal  folds  in  which  they  terminate ;  for  here  the  superincum- 
bent rock  has  been  worn  away  and  the  ore  itself,  or  the  iron  so  indicative  of  ore, 
brought  to  the  surface.  The  deposits  thus  outcrop  like  enormous  contact  veins, 
and  some  of  the  early  locators  took  their  claims  parallel  to  the  outcrop,  supposing 
they  could  follow  the  ore  with  the  pitch  for  an  indefinite  distance,  a  right  denied 
them  by  the  local  courts,  on  the  ground  that  the  ore  is  not  continuous  from  the 
outcrop  down. 


POSITION  OF   THE  DEPOSITS.  II 


POSITION  OF  THE  DEPOSITS. 

The  principal  mines  of  Leadville  are  situated  on  Fryer,  Iron  and  Carbonate 
Hills,  all  three  of  which  form  a  group  together  at  the  foot  of  the  Mosquito  or 
Park  Range  of  mountains.  The  distance  from  the  summit  of  Carbonate  Hill  to 
Fryer  Hill  is  about  one  mile  to  the  north,  and  from  the  same  point  to  the  top  of 
Iron  Hill  is  three  quarters  of  a  mile  south-east.  By  far  the  larger  portion  of  the 
ore  of  the  camp  is  derived  from  these  three  hills.  Fryer  Hill  has  so  far  produced 
the  most,  and  Iron  Hill  next.  It  is  Carbonate  Hill  that  principally  interests  us. 

Carbonate  Hill  lies  south-east  of  the  town  of  Leadville,  and  rises  directly  from 
its  outskirts.  Its  summit  rises  to  a  height  of  over  10,600  feet  above  the  sea-level, 
and  over  400  feet  above  the  main  street  of  Leadville.  To  the  east  it  slopes  gently 
to  the  valley  which  divides  it  from  Iron  Hill.  To  the  south  it  slopes  into  Califor- 
nia Gulch,  and  to  the  north  into  Stray  Horse  Gulch,  which  divides  it  from  Yan- 
kee and  Fryer  Hills.  The  claims  which  now  have  shafts  sunk  are  situated  along 
the  western,  south-western  and  north-western  slope  of  the  hill,  and  the  oldest,  in- 
cluding the  Carbonate,  Glass-Pendary,  JEtna,  Catalpa,  Evening  Star,  Morning 
Star  and  Henriette,  are  along  the  outcrop  of  the  ore-horizon,  which  approxi- 
mately follows  a  contour  about  200  feet  below  the  summit  of  the  hill.  This  outcrop, 
unlike  the  others,  is  covered  with  very  little  wash,  much  less  than  on  Fryer  Hill, 
yet  it  was  late  in  being  discovered.  The  distance  of  this  outcrop  to  the  Iron 
fault  is  about  three  quarters  of  a  mile. 

The  Evening  and  Morning  Star  mines  lie  side  by  side  on  the  north-western 
slope  of  the  hill.  The  former  lies  to  the  south-west  of  the  latter.  The  Blue  lime- 
stone outcrops  on  the  lower  quarter  of  each  claim.  The  Evening  Star,  though 
one  of  the  best,  is  one  of  the  smallest  mines  in  the  camp.  It  is  a  little  less  than 
half  a  claim  in  size,  being  1305  feet  long  by  163  feet  wide,  or  less  than  five  acres 
in  area.  Its  bonanza  was  so  thick  and  covered  so  much  of  its  area  that  it  has 
afforded  an  enormous  quantity  of  ore.  Its  location  was  in  fact  an  extremely  for- 
tunate one,  for  it  cut  the  great  ore-body  of  this  part  of  the  hill  through  its  thick- 
est and  richest  part.  If  the  nature  of  the  body  had  been  exactly  known  a  better 
belt  of  this  width  could  not  have  been  chosen  across  it.  To  the  south  the  ore  be- 
gins to  thin  into  the  Catalpa,  and  to  the  north  into  the  Morning  Star,  and  it 
never  again  approaches  in  either  of  these  mines  the  thickness  it  attained  in  the 
Evening  Star. 

The  Morning  Star  mine  lies  next  to  the  Evening  Star.  It  is  a  consolidation 
of  a  number  of  smaller  claims,  of  which  the  old  Morning  Star  and  Waterloo 
claims  are  the  most  important.  It  extends  in  width  to  the  Henriette  line,  a  dis- 
tance of  about  502  feet.  Its  eastern  boundary  is  continuous  with  that  of  the  Eve- 


12  OCCURRENCE  OF   THE  ORES. 

ning  Star,  but  it  extends  further  down  the  hill  than  the  latter  claim.  The  lower 
part  of  this  property,  however,  is  of  little  or  no  value,  and  there  are  now  no  work- 
ings run  below  1300  feet  from  the  east  end.  The  relative  size  of  the  claims  may  be 
seen  on  Plate  II.  In  both  mines  the  ore  occurs  immediately  below  porphyry  and 
in  Blue  limestone,  as  will  be  later  fully  described. 

GEOLOGICAL  STRUCTURE  AT  THE   MINES. 

The  Evening  Star  mine  is  principally  worked  through  four  shafts.  A  fifth, 
now  unused,  is  near  the  Forsaken  shaft.  A  sixth,  No.  9,  Plate  IV,  has  never  had 
a  drift  run  from  it.  It  has,  however,  greatly  aided  in  a  thorough  understanding 
of  the  formation,  for  it  has  been  sunk  nearly  200  feet  into  the  Blue  limestone  hori- 
zon, and  from  this  point  a  diamond-drill  boring  has  exposed  the  succeeding  strata 
for  200  feet  more,  and  has  thus  given  a  key  to  the  nature  of  the  underlying  for- 
1  mations.  The  Morning  Star  is  worked  through  four  shafts  on  its  own  property, 
and  a  fifth  on  the  Evening  Star  ground,  sunk  conjointly  by  the  two  companies 
and  used  alternately  by  them.  Three  other  shafts  have  been  occasionally  used 
but  are  now  idle,  and  numerous  prospecting  shafts,  or  rather  pits,  also  aid  in  study- 
ing the  formation.  The  fact  that  the  Morning  Star  is  a  consolidation  of  several 
claims  explains  the  existence  of  so  many  shafts.  The  new  McHarg  shaft,  now 
being  sunk,  was  started  October  1882,  and  is  the  only  one  that  the  present  com- 
pany has  started.  These  numerous  shafts  and  the  underground  workings  which 
connect  certain  of  them  together  have  given  a  complete  key  to  the  geological 
structure.  The  data  from  which  the  conclusions  are  deduced  are  given,  and  ac- 
companying these  are  two  cross-sections,  one  through  each  mine.  One  of  these 
sections,  Plate  III,  is  through  the  Morning  Star,  and  is  made  along  the  dip  of  the 
beds.  The  shafts  are  projected  on  this  plane  and  their  depths  given.  A  line  of 
levels  was  run  over  the  surface  to  determine  the  relative  heights  of  the  shafts  at 
the  top.  The  Evening  Star  is  such  a  narrow  claim  that  all  the  shafts  lie  nearly  in 
one  plane  in  that  section.  The  same  number  indicates  a  particular  shaft  on  the 
plan,  Plate  II,  and  on  the  sections,  Plates  III  and  IV.  The  numbers  indicating 
the  various  shafts  are  as  follows : 

1.  Upper  Waterloo  shaft. 

2.  Morning  Star  main  shaft. 

3.  Boarding-house  shaft. 

4.  Discovery  shaft. 

5.  Old  Waterloo  shaft. 

6.  Lower  Waterloo  shaft. 

7.  Forsaken  shaft. 


THE  MORNING  STAR   SECTION.  13 

8.  Old  Forsaken  shaft. 

9.  Evening  Star  No.  5  shaft. 
10.  Evening  Star  main  shaft, 
u.  Evening  Star  upper  shaft. 

THE  MORNING  STAR  SECTION. 

The  deepest  shaft  pf  this  section  is  No.  i,  the  Upper  Waterloo.  It  is  the  one 
furthest  up  the  hill.  This  shaft  begins  in  the  White  porphyry  and  passes  through 
it  for  a  distance  of  360  feet.  At  this  point  the  contact  between  the  latter  rock 
and  the  Blue  limestone  is  reached,  and  fine  ore  is  immediately  struck.  The 
second  level,  not  shown  in  the  section,  is  45  feet  below  this  point,  and  from  here  a 
drift  runs  to  the  end  of  the  property  120  feet  distant,  where  contact  is  again 
reached.  All  this  region  shows  large  bodies  of  fine  lead-ore,  which  is  indicated 
by  pen-dotting  on  both  sections  wherever  it  occurs.  Below  the  Upper  Waterloo 
the  Morning  Star  main  shaft,  No.  2  on  the  section,  is  the  next.  The  surface  at 
this  point  is  33  feet  lower  than  at  No.  i.  The  shaft,  always  measuring  from  the 
collar,  which  in  this  case  is  a  distance  above  the  surface,  is  265  feet  deep  to  con- 
tact. From  here  a  main  track  incline,  not  shown  in  section,  runs  immediately 
below  the  porphyry  and  along  the  contact  to  the  end  of  the  claim,  a  distance  of 
480  feet.  This  incline  is  connected  with  the  Upper  Waterloo  workings  in  several 
places,  and  the  contact  is  always  regular  and  void  of  all  signs  of  disturbance. 
The  Boarding-house  shaft,  or  what  Emmons  calls  the  Lower  Morning  Star,  is 
about  680  feet  below  the  Upper  Waterloo.  It  is  shown  on  the  plates  as  No.  3. 
This  shaft  passes  through  75  feet  of  White  porphyry  to  contact.  It  is  connected 
with  the  shafts  above  by  workings  which  show  the  porphyry  to  be  continuous  all 
the  way  along,  and  undisturbed  by  any  break.  No.  4  on  the  section,  which  is 
merely  a  prospect-shaft,  sinks  only  38  feet  to  contact,  and  here  an  incline  runs  for 
some  distance,  between  ico  and  200  feet,  and  shows  a  regular  contact. 

If  we  connect  the  points  where  these  shafts  pierce  the  surface  and  those 
where  they  strike  the  .contact  we  will  have  a  section  of  the  White  porphyry,  and 
by  producing  these  lines  down  the  hill  till  they  meet  we  have  the  point  where 
the  White  porphyry  ceases.  Immediately  below  the  Blue  limestone  outcrops,  or 
rather  what  was  once  the  Blue  limestone,  for  it  is  here  for  the  most  part  replaced 
by  vein  matter,  chiefly  oxides  of  manganese  and  iron.  This  outcrop,  in  spite  of 
the  wash  being  in  considerable  thickness,  is  very  plainly  marked  by  the  numerous 
boulders  of  iron-ore  which  are  scattered  in  a  broad  belt  along  the  face  of  the  hill. 
It  curves  around  the  hill,  running  almost  due  east  across  the  Henriette,  and  fol- 
lowing the  contour  of  the  hill  quite  strictly.  Numerous  pits  sunk  by  early  pros- 
pectors along  this  zone  show  nothing  but  the  iron-ore  on  the  dump. 


14  OCCURRENCE  OF  THE  ORES. 

The  lower  shafts  belong  to  a  different  series,  as  they  develop  the  ore  under  a 
second  sheet  of  porphyry.  They  are  many  in  number,  but  occupy  little  space  in 
the  section,  as  they  all  start  near  the  outcrop  of  the  second  sheet.  Most  of  the 
shafts  have  struck  valuable  ore  here,  and  the  Henriette  has  all  her  ore  at  this  hori- 
zon. The  Forsaken  shaft,  No.  7,  Plates  II,  III,  and  IV,  sinks  80  feet  to  contact,  and 
25  feet  further  to  a  second  level,  from  which  a  drift  runs  to  contact.  Owing  to 
there  having  been  no  record  kept  of  the  ground  passed  through  in  sinking  this  or 
any  of  the  other  shafts,  it  was  difficult,  and  in  one  case  impossible,  to  note  the  se- 
quence of  the  layers  or  sheets  passed  through  by  them.  In  this  shaft  and  in  the 
Old  Waterloo  this  was  only  obtained  by  climbing  the  ladders  and  looking  between 
the  round  timbers  whenever  these  were  wide  enough  apart.  It  was  especially 
difficult  to  do  this  in  the 'Forsaken  shaft,  as  the  walls  were  generally  some  dis- 
tance from  the  cribs  and  the  intervening  space  was  filled  with  wooden  blocks.  At 
the  top  there  was  only  wash,  boulders  of  iron-ore  mixed  with  water-worn  pieces  of 
porphyry.  More  solid  iron  appeared  below  this  and  continued  very  nearly  to  the 
porphyry.  Here  a  zone  of  impure  though  undoubted  limestone  occurred,  which 
could  be  traced  for  4  or  5  feet  above  the  porphyry.  Small  pieces  pried  out 
showed  the  rock  to  be  highly  impregnated  and  .discolored  by  metallic  oxides, 
though  it  effervesced  freely-with  warm  dilute  acid.  At  35  feet  from  the  surface 
Gray  porphyry  was  entered,  and  this  rock  continued  to  the  first  level,  46  feet 
below.  The  layers  passed  through  by  this  shaft  were  then  as  follows :  Wash,  1 5 
feet;  iron-ore  in  place,  from  15  to  30  feet;  limestone  in  place,  from  30  to  35  feet; 
porphyry,  from  35  to  8 1  feet. 

Below  the  Forsaken  this  sheet  of  Gray  porphyry  outcrops,  as  shown  by  the 
Old  Forsaken  shaft,  No.  8,  Plate  III,  which  begins  in  that  rock,  and  strikes  the 
contact  and  ore  at  only  25  feet  below  the  surface.  The  Forsaken  workings  follow 
the  ore  right  to  the  outcrop,  where  the  ore  and  wash  mix  with  each  other.  The 
Portland  shaft,  not  shown  in  the  section,  is  a  little  further  down  the  hill  and  does 
not  touch  the  porphyry,  but  sinks  down  through  iron-ore  far  below  the  ore- 
horizon  and  into  barren  ground. 

The  Old  Waterloo  shaft,  No.  5  in  the  section,  affords  the  best  view  of  the 
ground  along  the  zone  below  the  White  porphyry.  This  shaft,  which  is  135  feet 
deep,  strikes  the  contact  at  129  feet.  There  is  but  one  level,  from  which  two 
drifts  are  run ;  one  horizontal,  following  the  strike  of  the  porphyry,  and  one  an 
incline  which  follows  the  dip.  The  latter  is  shown  on  the  section.  The  same  iron- 
boulders  and  wash,  merging  into  iron-ore  in  place,  was  passed  through  as  in  the 
Forsaken.  At  a  depth  of  63  feet  limestone  appeared,  which  soon  became  solid 
and  quite  pure,  and  which  continued  for  18  feet.  At  the  top  of  this  limestone 
layer  there  were  seams  of  yellowish  and  much  decomposed  rock  which  resembled 
precisely  some  of  the  limestone  found  below  the  porphyry.  Lower  down  the 


THE  MORNING  STAR  SECTION.  15 

rock  became  massive  and  as  pure  as  any  encountered  below  the  porphyries  either 
in  the  Morning  or  Evening  Star.  The  color  of  the  more  pure  was  hardly  changed 
from  the  normal  blue.  The  bedding-planes  were  plainly  marked  and  corre- 
sponded in  dip  to  all  the  sedimentary  formations.  The  Gray  porphyry  began 
below  this  limestone.  The  contact  between  the  two  was  finely  shown,  and  the  dip 
of  the  porphyry  sheet  was  markedly  different  from  that  of  the  limestone  layers, 
being  much  steeper.  The  existence  of  this  limestone  in  place  above  the  porphyry 
is  alone  sufficient,  if  there  were  no  other  proofs,  to  show  that  this  sheet  is  a 
different  one  from  the  main  sheet  above. 

As  to  the  Lower  Waterloo  shaft,  it  could  not  be  examined,  so  that  the  thick- 
ness at  that  point  is  not  known.  A  rough  record  kept  of  the  ground  passed 
through  in  sinking  the  Evening  Star  shaft  No.  5  (No.  9,  Plate  IV)  shows  it  to  have 
there  had  a  thickness  of  50  feet. 

It  will  be  seen  on  referring  to  the  section  that  the  Gray  poryhyry  has  a  much 
steeper  dip  than  the  White.  This  dip,  though  it  has  been  maintained  as  far  as  de- 
velopment has  gone  beneath  it,  may  lessen  further  down.  Thus  far  it  has  cut 
across  the  limestone  bedding  to  a  lower  horizon.  Its  course  below  the  point 
where  development  has  been  carried  is  unknown.  The  course  it  probably  takes  is 
indicated  in  the  section,  this  part  of  the  outlines  of  the  sheet  being  put  in  in  broken 
lines.  The  Gray  porphyry  has  been  followed  over  400  feet  from  the  Lower 
Waterloo  shaft.  This  distance  takes  it  far  under  the  White  porphyry  sheet.  In 
fact,  directly  over  the  line  of  this  incline,  and  only  205  feet  from  the  shaft,  there  is 
an  old  shaft  but  20  feet  deep,  which,  though  the  bottom  is  filled  up,  shows  walls  of 
White  porphyry,  solid  and  apparently  in  place.  Consequently  the  Gray  porphyry 
has  been  traced  at  least  200  feet  beneath  the  White. 

The  evidence  of  a  second  sheet  of  porphyry  of  no  great  thickness  existing 
below  the  main  sheet  is  therefore  indisputable.  This  fact  is  recognized  by 
Emmons,  who  mentions  that  the  Half-way  House  and  Henriette  claims  are  on  it, 
but  owing  to  the  undeveloped  condition  of  the  ground  at  the  time  of  his  survey 
he  did  not  think  that  the  Forsaken  was  under  the  same.  He  considered  the  For- 
saken and  the  Lower  Evening  Star  shaft  (No.  9,  Plate  IV)  to  be  under  White  por- 
phyry, but  cut  off  from  the  rocks  above  by  a  fault  (the  Carbonate  fault)  whose 
western  wall  had  fallen.  This  fault  he  thought  also  ran  above  the  Waterloo  shafts. 
Recent  workings  have  shown  the  Forsaken  and  Lower  Waterloo  to  be  under 
the  same  sheet  of  porphyry,  for  they  are  connected,  and  pay-ore  runs  from  one 
shaft  to  the  other  almost  without  a  break.  Moreover,  it  has  been  shown  that  the 
White  porphyry  is  broken  at  no  point  from  the  upper  end  of  the  claim  to  the 
point  where  it  ceases,  and  that  the  Gray  porphyry  runs  beneath  it  without  a 
break  for  at  least  200  feet.  Consequently  there  can  be  no  fault  between  the  upper 
and  the  lower  shafts.  Acknowledging  the  existence  of  a  second  sheet  of  por- 


1 6  OCCURRENCE  OF   THE  ORES. 

phyry  alone,  there  can  be  no  doubt  of  this,  for  then  there  is  no  possible  room  for 
the  displacement  such  a  fault  would  cause. 

The  Gray  porphyry  goes  unbroken  to  its  outcrop.  Below  this  no  ore  has  ever 
been  taken  out.  Some  of  the  shafts  below  this  outcrop  have  been  sunk  quite  deep, 
but  none  could  be  visited  as  work  was  abandoned  on  them.  Porphyry  was  cer- 
tainly never  struck  in  any  of  them.  The  Niles  and  Augusta,  just  below  the  Even- 
ing Star,  was  sunk  all  the  way  through  the  White  limestone  and  into  the  upper 
strata  of  the  Cambrian  quartzites,  so  that  these  lower  formations  must  come  quite 
near  the  surface  at  this  point.  No  shaft  along  the  foot  of  the  hill  strikes  White 
porphyry.  The  fact  that  the  fault  does  not  lie  above  the  outcrop  of  the  second 
sheet  of  porphyry  by  no  means  proves  that  one  does  not  exist  below.  If,  however, 
it  does  exist  below,  the  displacement  must  be  much  greater  than  that  inferred 
by  Emmons  (170  feet).  It  seems  more  likely  that  the  outcrop  of  the  Blue  lime- 
stone marks  the  crest  of  an  anticlinal  fold  which  the  beds  make  at  this  point,  and 
which  has  been  eroded  until  the  White  porphyry  cap  has  been  worn  completely 
away. 

The  section  through  the  Evening  Star,  Plate  IV,  has  been  used  in  this  descrip- 
tion as  well  as  the  other  section,  Plate  III.  It  shows  little  that  has  not  already 
been  mentioned.  In  this  section  the  Gray  porphyry  is  seen  to  send  up  a  wedge- 
shaped  dike  into  the  limestone,  which  almost  reaches  the  White  porphyry.  Such 
dikes,  breaking  up  from  the  lower  sheet,  occur  elsewhere. 

To  sum  up,  the  following  are  the  important  points  regarding  the  ore-bearing 
sheets  : 

(1)  All  the  formations  dip  towards  the  south-east  (£.25°  to  30°  S.).    To  this  there 
is  no  exception.     At  the  same  time  the  surface  rises  towards  the  south-east. 

(2)  The  upper  sheet  of  White  porphyry  is  not  continuous  over  the  face  of  the 
hill,  but  the  Blue  limestone  outcrops  below  it. 

(3)  A  second  sheet  of  porphyry  different  from  the  first  lies  below  it.     The 
intervening  space  of  about  175  feet  is  taken  up  by  vein-matter  or  Blue  limestone. 

(4)  No  porphyry  sheet  of  any  kind  has  yet  been  developed,  and  no  ore  found 
below  the  outcrop  of  this  second  sheet  of  porphyry. 

(5)  The  formations  from  the  eastern  end  of  the  properties  to  the  outcrop  of  the 
second  sheet  of  porphyry  (Gray  porphyry)  are  undisturbed  by  fault  or  fold. 

The  formation  below  the  Gray  porphyry  is  well  shown  by  the  No.  5  shaft  of 
the  Evening  Star  (No.  9  on  Plate  IV),  or  rather  by  the  core  of  a  diamond-drill 
boring  made  from  the  bottom  of  it.  A  meagre  record  preserved  of  the  ground 
passed  through  in  sinking  this  shaft  gives  only  the  depth  at  which  Gray  porphyry 
was  struck  and  the  thickness  of  the  sheet.  As  the  shaft  was  not  in  use  and  had  no 
ladders  it  could  not  be  examined^but  the  dump  showed  only  iron,  Gray  porphyry 
and  Blue  limestone,  but  no  parting  qnartzite.  The  drill-core  also  showed  no 


THE   WHITE  LIMESTON&.  fj 

trace  of  the  latter  stratum,  but  White  limestone  began  immediately.  This  rock 
continued  for  a  distance  of  only  100  feet,  and  then  the  sheet  of  Cambrian  quartzite 
came  in  and  the  rest  of  the  boring  was  in  this  formation.  There  was  no  way  of 
determining  the  exact  boundary  between  the  Blue  and  the  White  limestone,  and 
it  is  accordingly  put  in  in  broken  line.  It  will  also  be  seen  that  at  this  point  the 
White  limestone  has  not  its  average  thickness  (about  1 50  feet  according  to  Emmons). 


DETAILED  DESCRIPTION  OF  THE  VARIOUS  ROCKS. 

The  various  formations  and  their  order  of  occurrence  having  been  described, 
there  remains  to  be  given  some  idea  of  their  nature  and  characteristics  before 
leaving  them  and  passing  to  the  especial  consideration  of  the  ore-deposits  and 
vein-material  in  the  Blue  limestone  horizon.  The  different  rocks  will  be  taken  in 
order,  beginning  at  the  bottom  and  going  towards  the  top. 

THE  CAMBRIAN  QUARTZITES. — This  formation,  though  not  entirely  passed 
through  by  the  drill,  was,  in  all  probability,  nearly  pierced,  for  the  description  of  the 
strata  given  in  Emmons's  report  closely  tallies  with  the  section  here  exposed,  and 
would  lead  one  to  infer  this.  As  it  is,  the  lower  100  feet  of  the  boring  is  in  this  forma- 
tion. At  the  bottom  of  the  boring  the  rock  was  very  hard.  No  large  pieces  of  core 
came  up,  but  generally  coarse  powder  and  small  fragments  of  very  hard  quartzite  of 
dull  gray  color.  A  few  feet  further  up  the  ground  was  more  impure  and  contained 
much  ferruginous  material.  Numerous  assays,  made  by  Mr.  Bonner,  the  assayer 
at  the  Evening  Star  mine,  show  that  this  material  carried  silver.  One  sample  gave 
him  14^  ounces,  and  another  5  ounces ;  all  the  rest  ran  much  lower,.  An  assay  of 
material  very  near  that  which  ran  14^  ounces  gave  the  writer  only  if  ounces.  This 
impure  streak  ceased  8  feet  above  the  bottom  of  the  boring,  and  very  pure,  white, 
saccharoidal  quartzite  came  in  and  continued  with  but  one  break  for  60  feet.  The 
break  was  caused  by  an  impure  streak  10  or  12  feet  thick  near  the  bottom.  At  70 
feet  from  the  bottom  the  quartzite  began  to  be  impure.  Red,  iron-stained,  calcare- 
ous quartzite  came  in  which  at  times  showed  micaceous  specks.  The  succeeding 
space  of  25  or  30  feet  marks  a  gradual  change  into  the  White  limestone,  and  is 
occupied  by  layers  of  impure  rock  sometimes  containing  little  calcareous  matter 
and  sometimes  a  great  deal.  Some  of  these  layers  are  shaly,  and  one  streak  of 
very  fine-grained  argillaceous  shale,  soft,  slaty  and  of  even  texture,  occupied  a 
zone  of  8  or  10  feet  just  at  the  top  of  these  quartzites.  This  stratum  comes  in 
mixed  with  almost  pure  quartzite,  and  goes  out  mixed  with  impure  limestone. 

THE  WHITE  LIMESTONE. — The  White  limestone  comes  in  above  the  quartzite, 
but  the  change  is  so  gradual  that  no  point  can  be  taken  as  the  boundary  between 
the  two.  It  is  most  impure  and  siliceous  at  the  bottom,  but  is  characterized 


i8 


OCCURRENCE  OF  THE  ORES. 


throughout  by  a  high  percentage  of  silica.  It  contains  very  little  organic  matter. 
The  color  is  a  dirty  white  or  grayish,  very  different  from  the  characteristic  blue 
of  the  Blue  limestone.  An  analysis  of  this  rock  is  given  a  little  further  on.  The 
drill-core  showed  very  little  vein-matter  in  this  rock,  only  a  few  streaks  of  wad 
tilling  crevices.  These  occurred  near  the  upper  part  of  the  bed. 

THE  BLUE  LIMESTONE. — Although  this  rock  contains  all  the  ore,  and  though 
all  the  workings  are  situated  in  its  horizon,  the  drifts  seldom  directly  encounter 
the  rock,  as  they  run  where  the  ore  and  other  vein-matter  occur.  The  limestone 
has,  however,  been  struck  in  some  places  both  on  the  Evening  and  Morning  Star, 
and  especially  in  the  southern  workings  of  the  Forsaken  and  Lower  Waterloo. 
It  is  always  stained  and  altered  in  color,  and  more  or  less  highly  impregnated 
with  iron  and  manganese.  Some  of  the  shafts  which  have  been  sunk  deep  into  the 
formation  have  struck  more  pure  rock,  notably  the  upper  Evening  Star,  at  ico  feet 
below  the  White  porphyry.  An  old  quarry  on  the  side  of  Iron  Hill,  towards 
California  Gulch,  from  which  this  rock  used  to  be  taken  for  fluxing  at  the  smel- 
ters, shows  a  face  of  35  or  40  feet  of  very  pure  Blue  limestone.  Here  it  is  massive 
and  deep  gray-blue  in  color.  It  shows  the  bedding-planes  very  perfectly.  The 
only  thing  that  breaks  its  homogeneity  is  the  narrow  streaks  of  calc-spar  which 
have  frequently  separated  along  the  bedding-planes.  The  rock  splits  easily  along 
the  bedding-planes,  so  that  flat  plates  may  be  split  off  six  inches  or  more  across. 

An  analysis  shows  the  Blue  limestone  to  be  a  very  pure  dolomite.  The  rock  in 
the  mine  resembles  the  rock  exposed  in  the  quarry  in  every  way  except  purity  and 
homogeneity  of  color.  The  specimen  already  referred  to  from  the  upper  Evening 
Star  shaft  was  just  like  the  quarry  rock,  even  in  color,  but  was  the  only  perfectly 
pure  specimen  found  in  either  mine.  Wherever  found  elsewhere  it  was  always 
stained  brown  by  manganese  and  iron,  and  altered  in  composition  by  the  addition 
of  these  ingredients  and  of  silica.  The  bedding  is  always  easily  recognizable  even 
when  in  a  very  much  altered  state.  Below  are  given  three  limestone  analyses.  No. 
i  is  of  the  White  limestone  ;  No.  2  is  of  a  pure  specimen  of  Blue  limestone  from  the 
quarry  on  Iron  Hill ;  No.  3  is  of  a  very  much  altered  specimen  of  Blue  limestone 
from  near  the  White  porphyry  in  the  Upper  Waterloo. 


I 

2 

3 

6  87 

Iron  sesquioxide  and  alumina.  

i  18 

o  28 

i  -*8 

28  64 

Magnesia  

i*  48 

46   80 

Sulphur  trioxide  

O7 

nc 

Phosphorus  pentoxide  

Organic  matter  ,  .    . 

jo 

IOO.O6 

100.05 

99.91 

THE   GRAY  PORPHYRY.  19 

The  very  high  percentage  of  silica  in  the  White  limestone  is  characteristic  of 
that  rock.  The  very  low  percentage  of  silica  in  No.  2.  is  prominent.  No.  3  has 
probably  derived  much  of  its  silica  from  the  porphyry,  which  is  but  a  few  feet 
from  it.  This  analysis  may  represent  the  composition  of  the  deeply  stained  rock 
occurring  elsewhere  in  the  mines. 

The  jointed  structure  in  this  stained  rock  is  always  distinct,  and  it  is  a  very 
significant  fact  that  wherever  found,  whether  as  isolated  "  boulders"  in  vein-matter 
or  in  large  bodies,  the  dip  is  always  the  same.  The  ore  and  vein-material  found 
at  this  horizon  will  form  the  subject  of  the  following  chapters. 

THE  GRAY  PORPHYRY. — This  rock,  where  exposed  to  view  by  the  workings,  lies 
entirely  in  the  Blue  limestone  and  in  the  lower  part  of  that  formation.  As  the  sec- 
tions show,  it  corresponds  in  dip  very  closely  to  the  enclosing  rock  for  a  distance  of 
150  to  200  feet  from  the  outcrop,  but  from  a  point  just  above  the  Lower  Waterloo 
shaft  it  takes  a  much  steeper  dip  and  cuts  down  across  the  limestone  stratum  to  a 
lower  horizon.  Probably  it  again  takes  the  dip  of  the  formation  lower  down 
(Emmons).  It  is  not  at  all  improbable  that  originally  this  sheet  continued  to  rise 
across  the  Blue  limestone  until  it  reached  the  White  porphyry,  and  that  the  point  of 
juncture  is  now  entirely  worn  away  by  erosion.  The  steeper  dip  is,  on  the  whole, 
very  regular  from  the  Lower  Waterloo  shaft  as  far  down  as  the  incline  has  been 
run,  but  there  are  many  minor  local  irregularities  in  the  pitch  which  often  seem 
to  bear  some  relation  to  the  deposition  of  ore.  These  will  be  mentioned  later  on. 

The  popular  name  for  this  rock  is  Bird's-eye  porphyry,  on  account  of  its  spotted 
appearance,  due  to  the  separation  of  feldspar  crystals  from  the  ground-mass.  It 
differs  very  much  from  the  White  porphyry,  even  when  both  exist  in  a  very  de- 
composed condition  side  by  side.  This  sheet  of  rock  is  so  thin,  being  only  from 
46  to  50  feet  in  thickness,  and  has  been  so  subjected  to  decomposing  agencies,  that 
an  approximately  fresh  specimen  could  nowhere  be  obtained.  Consequently  no 
analysis  of  the  rock  was  made,  as  it  was  thought  that  one  would  give  no  idea  of 
the  original  composition  and  nature  of  the  rock.  Even  at  the  centre  of  the  sheet, 
where  the  firmest  specimens  of  the  rock  were  found,  kaolinization,  which  is  the 
peculiar  form  of  decomposition  of  this  rock,  had  reached  an  advanced  stage,  and 
all  the  specimens  were  softened  and  crumbled  when  dry.  The  feldspar-crystal 
outlines  could  be  recognized.  They  occur  with  great  frequency,  ordinarily  as 
small  grains  a  sixth  to  an  eighth  of  an  inch  in  diameter.  Very  rarely  the  outlines 
of  much  larger  crystals  an  inch  or  so  in  length  could  be  recognized.  They  are 
always  soft  and  almost  completely  changed  to  clay. 

The  quartz  exists  as  small,  vitreous,  transparent,  white  crystals  about  as 
large  as  the  smaller  feldspar  crystals.  They  are  not  numerous,  but  any  small 
lump  weighing  an  ounce  or  so  would  be  likely  to  show  a  few  of  these  granules 
shining  through  it. 

The  ground-mass  is  generally  of  a  dull  gray  color  and  harder  than  the  rest. 


20  OCCURRENCE  OF   THE  ORES. 

The  feldspar  crystals  appear  as  granular  white  dots  through  it  and  occupy  about 
one  half  the  surface.  Sometimes  the  ground-mass  has  a  decided  pinkish  color, 
which  is  probably  due  to  the  oxidation  of  the  protoxide,  which  is  said  to  stain  the 
fresh  rock  greenish. 

It  is  not  an  uncommon  thing  for  branches  to  run  from  this  sheet  into  the 
formation  above,  and  even  to  extend  as  far  up  as  the  White  porphyry  and  to 
flatten  out  against  that  rock.  Such  a  dike  occurs  in  the  Evening  Star.  The 
main  shaft,  No.  10,  Plate  IV,  penetrates  it,  and  shows  that  it  comes  almost  to  the 
White  porphyry.  This  dike  is  shown  in  the  section.  Another  dike,  not  shown 
in  the  sections,  occurs  in  the  Morning  Star.  This  body  rises  all  the  way  up  to  and 
flattens  out  against  the  White  porphyry  and  cuts  off  the  ore-body  in  that  direction. 
Another  such  dike  occurred  in  the  workings  of  the  Boarding-house  shaft.  All 
of  these  dikes  show  all  the  characteristics  of  the  sheet  below,  and  have  also  de- 
composed in  a  like  manner. 

Immediately  along  the  lower  contact  of  the  Gray  porphyry,  except  where 
undecomposed  limestone  comes  in  direct  contact  with  it,  the  rock  has  been  com- 
pletely changed  to  clay  which  is  soft  and  perfectly  plastic  and  devoid  of  all 
signs  of  the  original  texture.  Further  from  the  contact  the  rock,  still  very  soft, 
begins  to  show  the  characteristic  mottled  appearance,  and  further  in  yet,  gen- 
erally two  or  three  feet,  it  becomes  firmer  and  the  jointed  structure  appears. 
Though  very  prominent,  the  jointing  is  not  carried  as  far  as  in  the  White  por- 
phyry, but  only  splits  the  rock  into  large  lumps. 

THE  WHITE  PORPHYRY. — The  White  porphyry  .is  a  more  regular  sheet  than 
the  Gray,  and  seems  to  follow  the  dip  of  the  Blue  limestone  with  great  regularity. 
The  facts  concerning  its  position  have  already  been  stated.  The  Brooklyn 
mine,  lying  east  of  the  Maid  of  Erin  (a  claim  adjoining  the  Morning  Star  on  the 
east),  finished  a  shaft  through  this  rock  last  fall,  so  that  a  section  through  500 
feet  was  exposed  on  the  dump  and  as  fresh  specimens  as  occur  were  obtainable. 
The  rock  is  light  gray  in  color  and  has  a  fine-grained,  even  surface  on  which  only 
very  few  porphyritic  ingredients  can  be  distinguished.  The  jointed  structure  is 
exceedingly  prominent  and  is  carried  very  far,  so  that  the  rock,  especially  if  at 
all  decomposed,  breaks  into  small  angular  blocks.  The  jointing  faces  are  always 
smooth  and  sometimes  have  an  almost  perfect  polish.  They  commonly  have 
stains  of  black  oxide  of  manganese  which  are  often  beautifully  dendritic  and  give 
rise  to  the  popular  name  of  forest-rock.  Besides  this  light  homogeneous-looking 
rock  a  peculiarly  banded  variety  is  found,  of  a  light  rusty  or  reddish-brown  color 
which  is  due  to  stains  of  sesquioxide  of  iron.  A  little  of  this  variety  occurred  in 
this  shaft.  In  other  places  on  the  hill  it  is  very  abundant.  Except  in  the  banded 
appearance,  which  is  only  due  to  the  coloring  matter,  it  does  not  seem  to  differ 
very  much  from  the  rest. 

The  macroscopic  crystals  are  scattered  very  thinly  through  the  fine-grained 


THE   WHITE  PORPHYRY.  21 

base.  QUARTZ  occurs  in  irregular  crystalline  granules,  not  more  and  generally 
less  than  o.i  inch  in  diameter.  They  are  colorless,  semi-transparent  and  vitreous, 
just  as  those  of  the  Gray  porphyry,  but  they  occur  much  less  frequently  than  in 
the  latter  rock.  MICA  is  of  more  frequent  occurrence  than  quartz.  Some  of  it 
exists  as  black  mica  or  biotite,  and  some  of  it  as  the  white  mica  or  muscovite,  the 
latter  being  a  product  of  the  decomposition  of  the  other  constituents.  The  biotite 
is  in  larger  pieces  than  the  muscovite,  but  is  less  frequent.  In  some  cases  it  is 
much  decomposed.  The  muscovite  is  fresher  than  the  biotite,  and  frequently 
shows  hexagonal  sections  very  nicely.  The  FELDSPAR  crystals  were  very  seldom 
recognizable  in  the  ground-mass.  Very  rarely  a  small,  shining  crystal  of  this 
mineral  could  be  seen  which  resembled  sanidine.  Orthoclase  is  the  essential 
feldspar  of  the  rock.  Many  cavities  now  empty  or  only  partially  filled  with  oxide 
of  iron  were  observed  in  this  rock,  and  though  none  of  them  contained  any  of  the 
original  mineral  which  once  filled  them,  it  is  probable  that  it  was  iron  pyrites,  all 
of  whose  sulphur  has  been  completely  washed  away. 

When  a  thin  slide  of  this  rock  was  examined  under  the  microscope  it  was 
found  to  be  a  true  felsite  or  quartz  porphyry,  though  it  has  been  much  altered  by 
secondary  changes.  The  feldspar  has  become,  as  a  rule,  opaque  from  kaolinization. 
The  ground-mass  was  fine-grained,  and  a  high  power  had  to  be  used  to  examine 
it.  The  porphyritic  ingredients  were  quartz  and  monoclinic  feldspar,  the  former 
predominating.  Between  or  about  the  larger  crystals  of  quartz  the  ground-mass 
was  sometimes  twisted  in  currents  with  a  peculiar  feathery  arrangement  of  the 
small  crystals  which  strongly  suggested  the  fluidal  texture.  In  another  slide  of 
the  banded  variety  mentioned  above  the  decomposition  had  proceeded  much 
further,  and  the  characteristic  features  could  not  be  seen  nearly  so  perfectly.  In 
both  sections  the  ground-mass  was  feldspathic,  but  contained  much  free  quartz  as 
tiny  angular  specks.  On  comparing  the  section  of  the  freshest  specimen  with  a 
number  of  slides  of  normal  quartz  porphyries  from  Europe  it  was  found  to  have 
a  precisely  similar  structure,  though  the  porphyritic  ingredients  were  generally 
larger  and  more  prominant  in  the  foreign  specimens. 

The  following  is  an  analysis  from  as  fresh  a  specimen  of  White  porphyry  as 
could  be  obtained,  yet  it  Has  evidently  lost  some  alkali : 

Silica 74.98 

Iron  sesquioxide l 

Alumina 1527 

Manganese  dioxide x  o_ 

L;me--: ..:.'".'  1.03 

MaSnesia trace 

Phosphorus  pentoxide . , 

Sulphur  trioxide ,  < 

Soda „ 

1. 80 

Potash 

2.10 

2.00 

99.61 


22  OCCURRENCE  OF   THE  ORES. 

It  is  true  that  the  White  porphyry  decomposes  and  gives  rise  to  large  bodies 
of  clay,  but  the  whole  rock  does  not  soften  in  this  manner  as  the  Gray  does. 
Commonly  it  decomposes  to  a  dry  siliceous  mass  in  which  the  jointing  is  per- 
fectly distinct  and  which  crumbles  to  small  bits  along  those  planes.  Such  decom- 
posed rock  caves  easily  and  has  to  be  supported  with  stout  timbers.  Ground  of 
this  kind  is  most  damaging  to  timbers,  not  so  much  because  it  swells  and  crushes 
them,  as  because  it  is  so  loose  that  it  caves  and  a  great  weight  of  rock  is  let  down 
on  them.  Where  the  rock  decomposes  to  a  soft  clay-like  product  this  caving  does 
not  occur  to  such  an  extent,  and  the  drifts  do  not  have  to  be  so  stoutly  timbered. 
Thus  beneath  the  Gray  porphyry  in  the  Lower  Waterloo  the  timbers  need  not 
be  nearly  so  strong  nor  so  close  together  as  under  the  White  porphyry. 


THE  ORE-DEPOSITS. 
THE  ORE-CURRENTS. 

The  position  of  the  ore  in  the  formations  is  shown  in  the  sections,  Plates  III 
and  IV,  by  pen-dotting.  It  occurs  in  the  horizon  of  the  Blue  limestone  and 
immediately  under  porphyry.  In  some  deposits  about  Leadville  the  ore  occurs 
in  White  limestone  and  other  formations,  but  by  far  the  larger  part  of  the  output 
of  the  whole  camp  comes  from  the  Blue  limestone,  as  in  the  Morning  and  Evening 
Star  mines.  The  contact  between  the  limestone  and  the  porphyry  is  also  the 
normal  position  of  the  ore,  especially  on  Carbonate  Hill,  but  there  are  important 
exceptions  to  this  rule  in  the  camp,  notably  in  the  deposits  of  the  Silver  Wave- 
Cord  group  on  Iron  Hill,  in  which  the  ore  occurs  as  lenticular  bodies  in  lime- 
stone and  in  no  way  connected  with  the  porphj-ry.  On  the  Morning  Star  a  large 
amount  of  ore  has  been  found  beneath  the  Gray  porphyry  sheet,  as  already  men- 
tioned. This  body  differs  in  no  essential  way  from  that  underlying  the  White 
porphyry,  the  ores  being  similar  and  the  laws  governing  their  occurrence 
the  same. 

Speaking  roughly,  we  may  say  that  the  Blue-limestone  bed  is  now  occupied 
by  two  classes  of  matter,  (i)  the  original  limestone,  and  (2)  vein -matter  of 
various  kinds  which  has  supplanted  the  original  rock.  Of  these  the  latter  class 
lies  immediately  under  the  porphyry.  The  limestone  is  below.  The  lower 
surface  of  the  porphyry  is  comparatively  even,  and  there  is,  as  a  rule,  an  abrupt 
boundary  between  it  and  the  vein-material.  Between  the  limestone  and  the  vein- 
matter  the  boundary  is  very  irregular.  Sometimes  the  vein-matter  is  so  thick 
that  it  almost  supplants  the  limestone,  and  again  so  thin  that  the  limestone  comes 


THE  ORE-CURRENTS.  23 

very  near  the  porphyry,  and  even  in  direct  contact  with  it,  pinching  out  the  min- 
eral matter  entirely.  Thus,  on  going  to  the  lowest  level  of  the  Evening  Star 
main  shaft,  No.  10,  Plate  IV,  and  following  the  drift  to  the  point  where  it 
emerges  from  the  Gray  porphyry,  limestone  is  found,  which,  however,  is  deeply 
stained  and  discolored,  while  numerous  heavy  seams  of  hydrous  oxides  of  iron  and 
manganese  run  along  the  bedding-planes.  It  is,  in  fact,  so  altered  that  there  can 
be  no  doubt  that  vein-matter  proper  would  appear  only  a  short  distance  above, 
though  the  ground  just  above  could  not  be  examined.  The  south-western  work- 
ings of  the  upper  shaft  of  the  same  mine,  No.  11,  Plate  IV,  show  a  quite  pure 
limestone  rising  up  to  contact  and  cutting  off  the  vein-matter  altogether. 

Though  the  vein-matter  occurs  along  the  contact,  it  by  no  means  occupies  all 
or  nearly  all  of  it.  Also,  it  does  not  occur  in  isolated  patches  which  have  no  rela- 
tion to  one  another.  It  is  found  to  follow  well-defined  courses  or  channels  in  the 
limestone  and  along  the  contact.  These  courses  are  much  longer  than  broad  and, 
though  they  vary  in  both  width  and  thickness,  are  perfectly  continuous  and  unin- 
terrupted. Such  streaks  have  been  excellently  named  ORE-CURRENTS. 

All  the  ore  is  found  in  these  currents.  The  larger  part  of  the  ore  of  the 
Morning  Star  and  almost  all  that  of  the  Evening  Star  has  come  from  one  great 
current  under  the  White  porphyry,  the  only  one  yet  developed  under  this  rock 
on  these  claims.  This  current  begins  on  the  western  slope  of  the  hill  in  the 
Crescent  claim.  It  starts  from  the  outcrop  and  passes  from  here  in  a  north- 
easterly direction  through  the  Catalpa  and  into  the  Evening  Star.  In  the 
Crescent  the  thickness  of  the  ore  alone  is  not  very  great,  but  it  becomes  thicker 
and  broader  in  the  Catalpa,  and  passes  into  the  Evening  Star  a  splendid  body 
which  rapidly  develops  till  an  enormous  thickness  is  reached,  the  maximum 
being  70  to  80  feet.  The  ore  in  the  current  as  rapidly  decreases  in  thickness 
towards  the  Morning  Star,  and  the  current  passes  on  much  thinner  but  broader 
and  still  bearing  fine  bodies  of  ore.  It  passes  through  the  south-eastern  part  of 
the  Morning  Star  consolidated  property  into  the  Maid  of  Erin  and  Big  Chief 
claims.  The  Brooklyn  shaft,  beyond  the  Maid  of  Erin,  also  strikes  ore  and,  as  it 
lies  in  the  right  direction,  is  almost  certainly  on  the  same  current. 

Below  the  Gray  porphyry  there  is  another  current  which,  though  not  nearly 
so  large  as  the  preceding,  contains  very  fine  bodies  of  rich  ore.  This  current,  as 
the  plan,  Plate  II,  will  show,  has  two  branches  which  run  into  the  hill  and,  joining, 
go  on  together  as  one  current.  One  of  these  branches,  the  smaller,  starts  at  the 
south-western  corner  of  the  Evening  Star  from  below  the  outcrop  of  the  porphyry 
and  runs  in  a  north-easterly  direction  toward  the  Old  Waterloo  shaft  (No.  6,  Plate 
II).  The  other,  larger  branch  begins  at  the  outcrop  on  the  old  Half-way  House 
claim  and  runs  a  little  south  of  east  into  the  Lower  Waterloo  and  Henriette,  the 
boundary  between  these  two  mines  being  about  the  centre  of  the  current.  Con- 


24  OCCURRENCE  OF   THE  ORES. 

tinuing  in  this  course  it  is  joined  by  the  smaller  branch.  This  ore-current  has 
lasted  as  far  as  developments  have  been  pushed,  and  there  is  every  reason  to  sup- 
pose that  it  will  continue  into  the  hill.  It  has  already  been  followed  from  the 
outcrop  to  a  depth  of  400  feet  below  the  surface,  and  the  breast  of  the  main  incline 
is  already  over  250  feet  beyond  the  point  where  the  outcrop  of  the  White  por- 
phyry ceases. 

The  pen-shading  on  Plate  II  and  the  pen-dotting,  Plates  III  and  IV,  repre- 
sent approximately  the  extent  and  depth  of  the  ore  alone  in  these  currents.  It 
would  be  more  difficult  to  give  the  boundaries  of  the  entire  current,  gangue  as 
well  as  ore,  as  the  gangue  is  not  followed  when  there  is  no  promise  of  ore.  If  the 
entire  amount  of  vein-material  were  represented  on  the  plates,  the  axis  of  the  cur- 
rent would  not  be  changed.  The  current  would  only  appear  broader  and  thicker. 
Of  the  area  represented  in  shading  on  Plate  II,  at  least  two  thirds  or  three  fourths 
is  occupied  by  pay-ore.  No  ore  occurs  outside  of  these  limits. 

Outside  of  such  a  current  the  limestone  comes  to  contact.  Under  the  White 
porphyry  it  is  not  often  met  with.  In  the  Morning  Star  it  was  found  in  only  two 
places,  and  there  it  was  altered  and  impregnated  with  impurities.  The  Boarding- 
house  shaft  showed  a  great  deal.  It  was  black  and  contained  so  much  iron  that  it 
became  strongly  magnetic  on  testing  with  the  blowpipe.  The  other  point  was  in 
the  face  of  drift  59  of  the  Upper  Waterloo,  where  the  same  characteristics  pre- 
vailed except  that  manganese  was  relatively  more  abundant.  These  two  points 
indicate  the  boundary  of  the  upper  current  on  the  north-east.  The  limestone  of 
the  upper  Evening  Star  shaft  (No.  u),  which  has  already  been  mentioned,  is  on 
the  southern  side  of  the  current. 

Below  the  Gray  porphyry  the  waste  vein-matter  does  not  extend  far  beyond 
the  point  where  the  ore  ceases,  and  the  boundary  of  the  current  is  better  denned. 
All  along  the  southern  side  of  the  smaller  branch  the  drifts  have  exposed  quite 
pure  limestone  coming  up  to  contact,  once  not  more  than  25  feet  from  where  the 
ore  ceased.  Limestone  is  likewise  found  in  the  barren  ground  just  above  the 
junction  of  the  two  branches.  The  northern  side  of  the  main  current  has  never 
been  determined.  It  extends  beyond  the  Henri'ette  and  perhaps  outcrops  along 
Stray  Horse  Gulch. 

These  are  the  only  currents  that  have  been  developed  on  the  property ;  and 
now  the  very  important  question  arises,  Do  any  others  exist,  and  if  so,  where  ? 
It  is  simply  impossible  to  say  whether  there  are  or  are  not  other  currents,  and  the 
only  way  of  finding  out  is  by  sinking  shafts  or  running  expensive  drifts  through 
barren  rock  to  the  unexplored  parts  of  the  mines.  As  to  where  they  will  be  found, 
if  they  do  exist,  of  course  the  answer  is  easier.  It  is  almost  certain  that  no  other 
body  of  ore  underlies  the  White  porphyry  in  the  Evening  Star,  for  the  unexplored 
area  in  that  mine  is  very  small.  In  the  Morning  Star  there  is  a  large  area  north- 


THE   VEIN-MATERIAL.  25 

west  of  the  main  current  which,  like  the  ground  beyond  it  on  the  Henriette,  is  as 
yet  undeveloped.  This  area  will  be  easily  explored  from  the  new  McHarg  shaft 
which  is  being  sunk  to  the  current  under  the  Gray  porphyry.  The  probabilities 
seem  to  be  against  there  being  another  current  in  this  ground  ;  for  if  there  is,  some 
of  the  old  prospecting-shafts  lower  on  the  hill  should  have  struck  it.  The  drifts 
that  will  be  run  from  the  new  shaft,  which  is  already  sunk  150  feet  below  the  con- 
tact (May,  1883),  will  solve  this  question. 

The  greatest  unexplored  area  is  on  the  second  contact;  that  is,  under  the 
Gray  porphyry.  It  is  the  entire  area  south-east  of  the  current  laid  open  under 
that  body.  This  ground  will  soon  be  explored,  for  both  the  middle  and  upper 
shaft  of  the  Evening  Star  (Nos.  10  and  n)  are  being  sunk  to  explore  it.  If  an  ore-, 
current  does  exist  there,  drifts  run  from  these  shafts  will  find  it.  In  the  mean 
time  the  results  of  exploration  have  to  be  awaited. 


THE  VEIN-MATERIAL. 

The  vein-material  as  it  now  exists  consists  of  carbonate,  sulphide  and  sul- 
phate of  lead,  sulphate  of  iron,  oxides  of  iron  and  manganese,  and  silica.  The 
latter  is  sometimes  in  a  very  pure  state  as  spongy  deposits  from  solution  or  as 
chert,  but  more  often  is  mixed  with  greatly  varying  proportions  of  oxide  of  iron. 
There  is  abundant  evidence  to  show  that  the  vein-materials  originally  existed  as 
sulphides  and  oxides  (or  carbonates),  but  owing  to  the  decomposition  of  the  former 
by  the  meteoric  agencies  to  which  they  have  for  ages  been  subjected  the  other, 
secondary  products  have  arisen.  In  the  original  deposits  the  minerals  form- 
ing them  occurred  pure  in  considerable  quantity,  but  the  larger  part  of  the  vein- 
material  consisted  of  mixtures  of  certain  of  them  in  almost  every  proportion. 
Consequently,  after  the  further  changes  due  to  the  action  of  meteoric  waters,  the 
variety  of  the  materials  going  to  make  up  the  vein-matter  is  very  great.  The 
number  of  pure  minerals,  however,  which  occur  in  the  deposits  is  very  small. 
The  following  were  noted : 

CERUSSITE,  lead  carbonate,  PbCO,. 

GALENITE,  lead  sulphide,  PbS. 

ANGLESITE,  lead  sulphate,  PbSO,;  Pyromorphite,  lead  phosphate  and 
chloride,  3Pb,P,O.+PbCl,. 

CERARGYRITE,  horn-silver,  containing  chloride,  bromide  and  iodide  of 
silver. 

CALCITE,  calc-spar ;  BARITE,  heavy  spar,  barium  sulphate,  BaSO, ;  Calamine, 
silicate  of  zinc ;  Native  silver ;  Pyrite ;  Rhodochrosite,  carbonate  of  manganese ; 


26  OCCURRENCE  OF   THE  ORES. 

Psilomelane,  hydrous  manganese  dioxide ;  Dechenite,  vanadate  of  lead  and  zinc, 
(Pb.Zn)  V,O, ;  BASIC  SULPHATE  OF  IRON. 

Of  these  minerals  the  ones  in  small  capitals  only  are  of  common  occurrence. 
Besides  the  well-defined  minerals  there  are  many  mixtures  of  manganese  and  iron 
oxides;  iron  oxide  and  silica;  silica,  iron  oxide  and  carbonate  of  lead,  etc.,  which 
exist  in  very  large  quantity  and  form  the  major  part  of  all  vein-material. 

The  vein-matter  may  be  most  conveniently  if  not  naturally  divided  into  ore 
and  gangue.  Concerning  the  position  of  these,  it  may  be  said  that  the  ores  occupy 
almost  identically  the  same  relation  to  the  gangue  that  the  whole  of  the  vein- 
matter  does  to  the  limestone.  The  ore  lies  immediately  under  the  porphyry,  and 
the  gangue  below  it.  The  ore  does  not  occupy  the  whole  surface  of  the  current, 
though  it  forms  a  continuous  sheet.  It  is  almost  always  found  in  strength  along 
the  centre,  but  the  gangue  always  rises  to  contact  along  the  sides.  The  thickness 
also  varies  greatly.  The  rule  that  where  the  ore  is  very  thick  the  gangue  below 
is  likewise  so,  and  vice  versa,  does  not  hold  at  all,  although  there  is  always  a  large 
amount  of  gangue  beneath  the  ore. 


THE  GANGUE. 

IRON-ORES. — These  consist  for  the  most  part  of  hydrous  oxides  of  iron  and 
manganese.  The  lower  half  or  three  quarters  of  the  current  is  largely  composed 
of  these  materials.  Further  up  towards  the  top  large  quantities  of  siliceous 
material  occur,  especially  in  the  upper  current.  These  mixtures  of  oxides  of  iron 
and  manganese  are  both  compact  and  loose.  The  loose  is  found  most  frequently 
near  the  top  of  the  zone  of  gangue  rather  than  at  the  centre.  It  also  occurs  near 
the  bottom,  and  frequently  forms  seams  in  the  limestone  and  about  boulders  of 
that  rock.  It  is  a  soft  wad-like  material,  but  does  not  powder.  It  can  be  easily 
dug  down  with  a  pick  and  falls  in  flakes.  It  contains  some  sulphuric  acid  which 
has  most  probably  been  derived  from  the  oxidizing  galena.  In  color  it  is  from 
dark  brown  to  black,  and  is  slightly  mottled. 

The  rest  of  the  lower  part  of  the  current  is  occupied  by  the  firmer  variety 
which  forms  the  greater  part  of  the  vein-material.  It  is  of  a  deep  blackish-brown 
color,  solid  and  hard.  It  has  a  well-marked  jointed  structure,  and  in  many  ways 
has,  when  in  large  masses,  the  outward  appearance  of  the  stained  limestone.  In 
both  currents  the  iron  is  in  such  a  high  state  of  oxidation  that  the  surveyor  uses 
his  compass  freely  in  the  mines.  All  the  manganese  exists  as  the  dioxide. 

The  following  analysis  represents  the  average  composition  of  this  material. 
The  specimen  was  taken  from  the  Lower  Waterloo. 


THE  SILICEOUS  GANGUE.  27 


Silica 10. 73 

Iron  sesquioxide 46.22 

Alumina 0.06 

Manganese  dioxide 31.18 

Lime 1.20 

Magnesia 0.68 

Water 9.98 

Phosphorus  pentoxide 0.05 

Sulphur  trioxide 0.03 

Carbonic  acid o.  54 


100.67 

THE  SILICEOUS  GANGUE. — This  exists  in  large  bodies  and  in  great  variety. 
It  occurs,  as  a  rule,  near  the  ores  and  both  above  and  below  them.  Low  down  in 
the  current  it  is  rare.  When  above  the  ore  and  along  the  contact  it  is  very  pure. 
It  is  then  often  a  spongy,  white,  amorphous  material,  with  hard,  cherty  cores,  and 
has  evidently  been  deposited  from  solution.  In  the  Lower  Waterloo  and  Forsaken 
there  is  a  large  sheet  of  compact  rock,  now  very  much  disintegrated,  but  showing 
a  jointed  structure  and  many  external  features  of  quartzite.  This  sheet  overlies 
all  the  ore  of  the  branch  current.  It  will  be  mentioned  later. 

The  siliceous  gangue  proper  belongs  below  the  ore,  and  occurs  in  large 
though  ill-defined  and  by  no  means  regular  or  continuous  bodies.  It  is  much 
more  common  under  the  White  porphyry  than  under  the  Gray.  It  is  never  pure, 
but  has  always  a  high  percentage  of  sesquioxide  of  iron.  In  its  purest  form  it 
exists  in  local  concretionary  deposits  of  a  red  jasper  imbedded  in  more  impure 
material.  It  is  then  much  harder  and  more  compact  than  the  rest  and  has  few 
joints  running  through  it.  As  long  as  the  percentage  of  silica  is  very  high  the 
rock  is  extremely  hard,  but  as  the  siliceous  character  becomes  less  prominent  and 
oxides  of  iron  and  carbonate  of  lead  appear  in  quantity  it  assumes  a  regular 
jointed  structure,  so  that  a  blow  of  a  hammer  will  shatter  the  brittle  rock  into 
small  angular  blocks.  The  most  common  variety  of  this  gangue  has  from  30  to 
50  per  cent  of  silica,  and  the  rest  is  made  up  of  sesquioxide  of  iron,  carbonate  of 
lead  and  a  little  water.  An  analysis  of  this  kind  of  material  is  given  below.  The 
specimen  is  very  rich  in  silver,  but  that  metal  came  almost  entirely  from  coatings 
of  cerargyrite  deposited  from  solution  along  the  joints  already  alluded  to. 

Silica 39-  50 

Silver  chloride 1.44 

Lead  oxide '5-46 

Iron  sesquioxide 35-6? 

Lime 0.50 

Carbonic  acid 3.44 

Water 3-46 

99-47 


28  OCCURRENCE  OF  THE  ORES. 

The  percentage  of  lead  carbonate  in  the  analysis  given  above  is  seen  to  be 
quite  large.  A  full  series  of  this  kind  of  rock  running  from  a  quite  low  percentage 
in  lead,  like  the  one  above,  to  a  quite  high  percentage  of  that  metal  occurs  in  the 
Morning  Star.  Very  little  of  it  comes  under  the  Gray  porphyry,  though  it  is 
even  then  occasionally  met  with.  In  both  the  Evening  and  Morning  Star  it  is 
abundant  under  the  White  porphyry.  Where  the  percentage  of  lead  is  low  the 
rock  is  generally  not  perfectly  homogeneous,  but  some  parts  of  it  contain  more 
lead  than  others. 

CLAYS. — The  small  quantity  of  alumina  in  the  vein-material  is  noticeable.  It 
exists  almost  exclusively  in  clays  which  may  be  traced  to  porphyry  as  a  source. 
All  the  largest  sheets — and  here  they  reach  considerable  proportions — lie  directly 
along  it,  and  the  very  small  quantity  existing  below  is  in  most  cases  plainly  due  to 
infiltration.  Along  the  upper  contact  clays  are,  comparatively  speaking,  scarce- 
For  the  most  part  the  White  porphyry  at  contact  does  not  kaolinize,  but  assumes 
a  hard,  dry,  siliceous  form  which  in  a  yet  more  advanced  stage  of  decomposition 
easily  crumbles  to  a  dry,  sandy  powder  and  shows  no  clay  at  all.  In  the  upper 
shaft  of  the  Evening  Star  and  in  the  Boarding-house  shaft  there  were  considerable 
bodies  of  clay  along  the  contact.  These  sheets  were  highly  impure  and  contained 
many  streaks  of  manganese  oxide  and  some  carbonates  of  lime  and  manganese. 

Clay  is  common  along  the  lower  contact.  The  Gray  porphyry  is  soft  and  tends 
to  change  to  clay,  and  generally  several  inches,  at  least,  of  very  pure  clay  lies  above 
the  vein-matter  proper.  Often  it  is  peculiarly  striped  and  stained  by  iron  and 
manganese.  It  is  very  pure  and  much  of  it  is  of  surprising  whiteness.  It  seldom 
contains  appreciable  quantities  of  sulphur.  That  all  these  clays  have  arisen  from 
the  decomposition  of  the  porphyry  in  place  there  can  be  no  doubt,  for  there  is 
always  a  gradual  change  from  the  pure  structureless  clay  without  to  undoubted 
porphyry  within.  The  thickness  of  these  clay  sheets  varies  from  a  few  inches  to 
two  or  three  feet. 

The  remarkable  clay  called  by  the  miner  "  Chinese  talc"  has  a  different  mode 
of  origin.  This  material  conies  in  the  mines  both  along  the  contact  and  below  it. 
The  black  iron  of  the  Lower  Waterloo  shows  many  pockets  of  it  which  are 
entirely  isolated  and  from  five  to  ten  feet  from  the  contact.  Some  of  it  is  stained 
by  manganese  and  iron,  but  most  of  it  is  pure  white.  It  has  a  conchoidal  fracture 
and  an  opalescent  or  pearly  lustre,  and  is  semitransparent  on  thin  edges.  On 
exposure  to  the  air  it  slowly  becomes  opaque,  especially  if  impure.  Some  speci- 
mens from  the  Carbonate  mine  which  were  soft  became  opaque  on  a  very  short 
exposure.  Two  specimens  from  the  Lower  Waterloo  were  analyzed.  No.  i  was 
the  softer.  It  was  stained  light  green  when  taken  out  of  the  mine.  On  six 
months'  exposure  it  became  opaque  on  the  surface  and  had  turned  to  a  pinkish 
color.  Within  it  was  still  fresh  and  green.  It  contained  only  a  faint  trace  of 


THE    ORES.  29 

manganese.     No.  2  was  much  harder  and  more  brittle,  and  remained  translucent 
on  thin  edges  even  after  half  a  year's  exposure.     The  following  are  the  analyses: 

(i)  W 

Silica 42.94  40. 53 

Alumina 37.  n  38.51 

Water 19.48  19.43 

Sulphur  trioxide 0.65  0.33 

Lime..     0.66  1.50 


100.84  100.30 

These  analyses  show  that  the  composition  is  variable,  though  No.  I  gives  the 
formula  Al,Si,O,3H,O  very  nicely. 

A  few  minerals  which  occur  in  the  deposits,  most  often  in  the  gangue,  may  be 
briefly  mentioned  here. 

CALCITE. — This  is  of  course  common ;  generally  it  occurs  as  the  ordinary 
incrustation  filling  crevices  in  the  waste  or  lining  cavities  in  the  iron.  In  the 
large  cavities  in  the  gangue  beautiful  crystallizations  are  often  found.  Large  and 
very  handsome  rhombohedrons  on  cerussite  occur  in  the  Evening  Star.  Much  of 
it  occurred  in  a  cave  found  in  the  workings  of  the  Boarding-house  shaft. 

BARITE. — Heavy  spar  in  small  quantities  is  also  very  common.  Generally  it 
is  found  scattered  through  ore  as  small  crystalline  aggregates  of  a  pure  variety. 
A  more  impure  kind,  of  pinkish  color,  is  found  in  larger  masses. 

CALAMINE. — This  mineral  is  far  more  rare  than  either  of  the  above.  It  is 
almost  always  found  in  waste,  most  frequently  in  the  Lower  Waterloo,  forming 
the  filling  of  crevices  and  druses.  It  occurs  in  aggregates  of  fine,  slender,  needle- 
like  prisms. 

DECHENITE. — Dechenite  has  been  found  in  very  small  quantity  in  the  Evening 
Star.  It  occurs  as  an  incrustation  on  a  siliceous  gangue.  When  thick  these 
coatings  are  of  a  deep  brick-red  color.  Surfaces  six  inches  across  have  been  found 
completely  covered  with  it.  It  yields  no  reaction  whatever  for  chlorine,  and  gives 
fine  reactions  for  vanadium,  lead  and  zinc  before  the  blowpipe. 

THE  ORES. 

There  can  be  no  doubt  that  the  lead  was  all  originally  deposited  in  the  lime- 
stone horizon  as  the  sulphide,  and  that  the  silver  was  either  deposited  along  with 
it  as  the  sulphide,  as  in  ordinary  argentiferous  galena,  or  perhaps  also  with  this, 
but  separated  out  as  argentite.  Besides  these  there  seems  to  have  been  deposited 
in  some  places  a  great  deal  of  iron  pyrites,  either  mixed  with  varying  propor- 
tions of  galena  or  nearly  free  from  it.  The  oxidation  of  these  sulphides  has  pro- 
ceeded so  far  that,  comparatively  speaking,  very  little  galena  is  now  left,  and 


30  OCCURRENCE  OF    THE  ORES. 

there  is  not  a  trace  of  iron  pyrites.  The  products  arising  from  this  decomposi- 
tion are  for  the  most  part  carbonate  of  lead,  chlor-bromide  of  silver  (containing 
also  some  iodide),  sulphate  of  lead  and  sulphate  of  iron.  The  original  sulphides 
formed  a  belt  along  the  contact.  In  most  places  the  change  to  the  oxidized  prod- 
ucts was  a  gradual  one  in  place.  Small  amounts  of  all  the  metals  were  carried 
off  in  solution  by  the  oxidizing  waters.  They  were  to  a  large  extent  redeposited 
in  the  gangue,  and  in  some  cases  sufficiently  concentrated  to  form  ore  out  of  what 
would  have  otherwise  been  too  poor  to  pay  for  extraction. 

The  galenas  occupied  the  upper  portion  of  the  belt  of  sulphides,  and  the 
pyrites,  where  it  occurred  in  any  quantity,  formed  a  belt  below.  The  galena  has 
changed  to  carbonate  of  lead,  and  the  pyrites  to  hydrous  basic  sulphate  of  iron. 
Any  galena  that  was  mixed  with  the  pyrites  has  likewise  changed  to  the  sulphate. 

The  three  sections  given  (Plate  I)  illustrate  the  position  of  the  ore  in  the  de- 
posits and  represent  the  different  zones  of  ore  and  gangue. 

Section  i  is  through  a  portion  of  the  ore-body  of  the  Upper  Waterloo.  The 
galena  has  entirely  changed  to  the  carbonate,  and  the  pyrites  to  the  sulphate  of 
iron.  The  former  is  represented  by  the  gray-blue  band  immediately  under  the 
White  porphyry,  and  the  latter  by  the  yellow  band  below  the  blue.  The  latter 
zone  was  not  rich  enough  to  pass  as  ore,  and  its  lower  boundary  could  not  be 
accurately  determined,  as  it  was  seldom  exposed.  It  is,  however,  very  nearly  the 
same  as  that  given  in  the  section.  All  the  other  lines  on  the  plate  are  from  actual 
measurements.  The  boundary  between  the  carbonate  and  sulphate  is  abrupt  and 
well  denned,  as  is  that  between  the  latter  and  the  iron-ore  lying  below  it. 

Section  2  is  through  a  part  of  the  small  branch  current  of  the  Lower  Water- 
loo. The  same  description  holds  here  as  in  the  former  case.  The  blue  belt  is 
very  highly  oxidized  lead-ore,  rich  in  lead  but  containing  some  silica,  and  by  no 
means  as  pure  as  the  preceding.  The  yellow  zone,  which  in  this  case  is  fine  ore, 
occupies  the  same  position  as  in  the  other  section.  In  this  section  the  current  is 
not  very  deep,  and  the  stained,  impure  limestone,  is  indicated  in  the  lower  part  by 
the  conventional  lining. 

Section  3  is  also  from  the  Lower  Waterloo,  but  is  from  the  main  ore-current 
below  the  junction  with  the  branch.  This  body  of  ore  never  had  a  zone  of 
pyrites  below  it,  and  hence  there  is  no  yellow  sulphate.  The  cerussite,  which  is 
highly  ferruginous,  still  contains  many  nodules  of  galena.  The  iron  immediately 
below  is  somewhat  soft  and  contains  much  manganese  dioxide  and  some  sul- 
phuric acid.  It  soon  changes  into  the  firmer  variety. 

No  section  of  the  great  ore-body  of  the  Evening  Star  is  given,  as  it  was  for 
the  most  part  stoped  away,  and  there  was  no  way  of  getting  an  accurate  section 
representing  how  and  as  what  the  ore  occurred. 

THE  GALENA. — There  is  not  much  of  the  galena  left  in  the  ore-bodies,  though 


THE  GALENA.  31 

in  one  or  two  places  it  is  abundant.  It  occurs  nowhere  as  continuous  and  solid 
bodies.  It  everywhere  shows  signs  of  an  advanced  state  of  decomposition  into 
oxidized  products,  and  is  divided  into  nodules  by  seams  or  streaks  of  these.  It 
rarely  occurs  under  the  White  porphyry,  and  then  in  small  nodules  imbedded  in 
the  carbonate  of  lead,  and  seldom  over  a  few  inches  in  diameter.  It  is  most  abun- 
dant in  certain  parts  of  the  Lower  Waterloo.  No  galena  is  found  in  the  small 
branch  current  (Plate  II),  as  oxidation  has  there  been  very  complete,  but  in 
the  larger  branch  and  the  main  current,  especially  in  the  former,  it  is  quite 
abundant. 

The  ore  of  the  Half-way  House  mine,  below  the  Lower  Waterloo,  consisted 
mostly  of  this  mineral,  and  was  very  rich,  although  the  bodies  were  not  large. 
About  the  first  level  of  the  Lower  Waterloo  shaft  (No.  6,  Plate  II),  galena  occurs 
as  nodules  and  broken  streaks  surrounded  by  carbonate  of  lead.  Below  this 
point,  for  50  to  too  feet,  it  is  more  abundant  than  at  any  other  place  in  either 
mine.  Here  in  some  places  it  is  in  streaks,  alternating  with  seams  of  carbonate, 
and  together  with  this  forming  a  very  rich  pay-streak  two  or  three  feet  in  thick- 
ness. The  galena  streaks  are  bright  at  the  centre  but  lustreless  on  the  outside. 
They  are  not  solid,  but  in  several  main  streaks  and  numerous  branches  which 
form  a  network.  The  decomposition  products  are  deeply  iron-stained  to  a  rusty 
color.  The  galena  in  decomposing  first  loses  its  metallic  color  and  forms  a  dark 
band  of  greasy  lustre,  half  an  inch  in  breadth  ;  then,  while  the  streak  is  still  hard, 
the  brown  color  appears.  At  the  centre  of  the  broadest  of  the  streaks  of  car- 
bonate it  is  softer  and  granular.  The  galena  in  this  body  was  on  the  whole 
coarse-grained,  but  almost  every  texture  could  be  seen  even  in  different  parts  of 
one  and  the  same  seam  of  undecomposed  mineral. 

About  at  the  same  level  as  this,  but  over  on  the  Henriette  line,  galena  is 
found  in  great  abundance  and  with  very  little  carbonate  of  lead.  Here  it  is  along 
the  contact,  but  it  does  not  form  a  solid  streak.  It  occurs  as  a  series  of  streaks 
of  the  greatest  irregularity  running  through  and  lying  in  black  iron.  In  some 
cases  it  lies  directly  along  the  porphyry,  and  in  some  it  is  entirely  surrounded  by 
iron.  The  streaks  are  always  near  the  porphyry,  however,  and  the  zone  in  which 
they  occur  never  extends  more  than,  six  or  eight  feet  from  it.  These  streaks  are 
small  as  well  as  extremely  irregular,  but  rich  in  both  silver  and  lead.  The  iron- 
ore  about  it  contains  no  lead  and  far  too  little  silver  to  pay.  Assays  of  this  iron 
gave  6  to  20  ounces  of  silver.  The  decomposition  of  the  galena  was  slight,  but 
narrow  streaks  of  cerussite  ran  through  the  seams  and  divided  it  up  into  nodules 
which  were  both  bright  and  large,  many  of  them  weighing  50  or  ico  pounds. 
The  iron  in  which  they  occurred  was  somewhat  soft.  It  contained  much  manga 
nese  dioxide  and  some  sulphuric  acid. 

Below  the  junction  of  the  two  currents  galena  is  more  rare.     It  is  only  found 


32  OCCURRENCE  OF  THE  ORES. 

as  nodules,  and  these  are  mostly  small  and  imbedded  in  large  bodies  of  carbonate 
of  lead.  On  breaking  them  open  the  centres  are  always  bright.  Around  this 
core  there  is  a  zone  of  the  lustreless  sulphide,  and  then  this  changes  into  carbonate 
so  gradually  that  a  division  line  cannot  be  recognized  between  the  two.  The 
transition  of  the  galena  into  cerussite  is  always  plainly  shown. 

In  the  above  examples  there  is  every  step  from  nearly  solid  galena  in  which 
the  change  is  just  beginning,  to  the  almost  completely  oxidized  bodies  in  which 
there  is  scarcely  any  galena  left.  In  the  branch  current  of  this  contact,  and  also 
in  the  Upper  Waterloo,  we  have  bodies  in  which  the  changes  have  long  been 
completed.  The  change  is  an  altogether  gradual  one  from  without  inward,  and 
there  can  be  little  doubt  as  to  the  manner  in  which  it  is  effected.  The  oxygen 
dissolved  in  the  waters  penetrates  the  ore  and  oxidizes  the  galena  to  sulphate  of 
lead.  The  calcium  carbonate,  held  in  solution  in  the  water  by  an  excess  of  car- 
bonic acid,  acts  upon  the  sulphate  of  lead,  forming  carbonate  of  lead  and  sulphate 
of  calcium.  The  latter  passes  off  in  solution.  Alkali  carbonates  would  act  on  the 
sulphate  of  lead  in  the  same  manner. 

There  are  often  cavities  in  the  galena,  and  these  are  generally  lined  with 
large  transparent  crystals  of  cerussite.  They  are  then  in  long  prisms  capped  by 
the  pyramid. 

Galena  has  been  found  on  several  occasions  within  the  Gray  porphyry. 
Sometimes  it  forms  the  filling  of  irregular  gashes  which  run  up  into  the  rock  from 
the  contact,  but  which  are  always  very  small.  On  two  occasions  it  was  found 
forming  seamlets  in  it  four  or  five  feet  above  the  contact,  and  running  parallel  to 
it.  In  one  case  the  seam  was  over  a  foot  thick  and  mostly  carbonate  of  lead,  with 
galena  in  large  nodules.  In  the  other  the  seams  were  only  six  inches  thick,  but 
were  nearly  solid  galena. 

The  galena  is  generally  very  rich  in  silver.  Under  the  White  porphyry 
samples  were  too  rare  to  afford  trustworthy  estimates  of  the  general  run  of  the 
original  galena  of  the  upper  current,  but  under  the  Gray  porphyry  there  was  an 
abundance.  To  give  a  good  idea  of  the  richness  of  these  galenas  fifteen  speci- 
mens from  various  parts  of  the  Lower  Waterloo  were  assayed.  The  average 
silver  contents  was  180.2  ounces  per  ton  of  2000  pounds.  The  different  samples 
varied  greatly  in  value,  the  minimum  being  but  36  ounces  and  the  maximum  490. 
Four  of  the  fifteen  ran  less  than  75  ounces,  and  three  of  them  over  300.  A  small 
nodule  found  later  gave  by  assay  1142  ounces,  but  this  was  far  above  any  other 
sample  of  galena  found  in  either  mine.  The  percentage  of  silver  seems  to  be  in  no 
way  connected  with  the  texture  of  the  galena  or  its  crystalline  structure.  Almost 
all  the  galena,  coarse  or  fine,  is  rich,  but  both  coarse  and  fine  do  occur  which 
are,  comparatively  speaking,  very  poor  in  silver.  The  galena  in  the  Lower 
Waterloo  is  not  as  a  rule  very  pure.  Only  two  of  the  fifteen  assays  mentioned 


THE  PURE  CARBONATE  OF  LEAD  33 

above  gave  over  75  per  cent  of  lead.  Nine  of  them  gave  over  70  per  cent.  The 
average  of  the  fifteen  was  about  69  per  cent.  In  the  Upper  Waterloo  the  galena  is 
very  pure  and,  as  far  as  could  be  judged,  less  rich  in  silver.  The  impurities  are 
commonly  iron  oxide  and  silica,  chiefly  the  latter.  The  iron  is  generally  invisible. 
Only  one  piece  showed  tiny  specks  of  pyrites,  the  only  traces  of  this  mineral 
found  among  the  ores  in  either  mine. 

THE  PURE  CARBONATE  OF  LEAD. — This  is  and  has  always  been  the  chief  ore 
of  both  mines  and  under  both  sheets  of  porphyry.  The  purest,  largest  and  best- 
defined  bodies  of  carbonate  of  lead  occur  under  the  White  porphyry.  In  the 
Evening  Star  they  had  been  removed  before  the  fall  of  1882,  but  in  the  Morning 
Star  they  were  well  developed  but  not  stoped  out.  In  the  upper  levels  of  the 
Forsaken  and  Lower  Waterloo  there  is  another  body  of  large  extent,  though 
neither  so  thick  nor  so  pure,  but  very  completely  oxidized.  The  ores  of  the  lower 
levels  and  elsewhere  are  still  less  pure,  and  contain  the  galenas  already  mentioned 
as  well  as  iron  oxide  and  other  gangue.  The  purest  carbonate  of  lead  bodies  con- 
tain little  else  than  pure,  granular  cerussite  crystals,  often  so  loosely  put  together 
that  thev  easily  crumble  between  the  fingers,  especially  when  damp.  Some  of  it 
is  more  firmly  cemented  and,  especially  when  dry,  quite  firm  and  hard.  The 
grains  out  of  which  the  purest  bodies  are  formed  are  about  the  size  of  coarse  sand 
and  resemble  it  superficially.  They  consist  of  very  imperfect  crystalline  gran- 
ules, among  which,  by  the  aid  of  a  strong  magnifier,  a  more  or  less  perfect  prism 
may  occasionally  be  recognized.  They  are  of  course  very  brittle,  and,  whatever 
the  color  of  the  body  be,  the  powder  is  white.  It  is  for  this  reason  that  a  pick 
always  leaves  a  white  mark  in  this  ore. 

In  the  color  of  the  pure  cerussite  ore  there  is  great  variety.  Rarely  it  is  an 
almost  pure  white.  Brown,  grayish  brown  and  gray  are  the  most  frequent 
colors,  but  grayish  blue  is  also  common.  Sometimes  it  is  a  light  cream-color, 
sometimes  almost  black.  The  coloring-matter  is  mostly  oxide  of  iron,  more 
rarely  oxide  of  manganese,  and  only  forms  a  small  percentage  in  the  composition 
of  the  ore.  The  color  bears  no  relation  to  the  silver  contents,  and  rarely  to  the 
percentage  of  lead.  The  bodies  of  the  Upper  Waterloo  frequently  show  a  pecu- 
liar banded  structure,  very  faint  and  delicate,  and  entirely  in  the  coloring-matter. 
These  bands  can  be  plainly  seen  by  candle-light,  but  can  hardly  be  recognized  on 
the  surface.  They  consist  of  bands  of  slightly  different  color,  and,  though  gently 
wavy,  always  run  strictly  parallel  to  the  dip  of  the  body.  Almost  all  the  purest 
cerussite  ore  shows  this  banding. 

The  percentage  of  lead  in  these  ores  is  almost  that  of  normal  cerussite.  Two 
analyses  were  made,  one  from  the  ore  of  the  Upper  and  one  from  that  of  the 
Lower  Waterloo.  The  first  was  grayish  white  in  color,  the  second  bluish  gray. 


34  OCCURRENCE  OF   THE  ORES. 

(i)  (2) 

Gangue 0.42  4.43 

Leadoxide 83.27  77.70 

Silver  chloride '. 0.03  0.12 

Lime 0.80 

Carbonic  acid 16.30  14.56 

Sulphur  trioxide 0.32  0.28 

Phosphorus  pentoxide • 1 . 22 

Chlorine trace 

Moisture 0.50 


100.34  99.61 

These  two  analyses  represent  the  purest  ore  found  under  the  White  and 
Gray  porphyries  respectively.  The  first  is  almost  pure  cerussite.  The  second 
shows,  besides  gangue,  a  considerable  percentage  of  pyromorphite  (nearly  8  per 
cent). 

These  pure  carbonates  are  very  fine  ores  on  account  of  the  high  percentage 
of  lead  ;  for,  since  they  are  very  desirable  to  the  smelter,  a  high  price  per  pound  is 
paid  for  the  lead  in  them,  and  a  low  charge  deducted  for  treatment.  They  are, 
however,  poor  in  silver.  Wherever  the  ore  is  purest  and  oxidation  has  been  most 
complete  the  amount  of  silver  is  found  to  be  the  least.  In  the  Upper  Waterloo 
the  pure  cerussite  ore  with  only  a  few  per  cent  of  gangue  normally  runs  not  more 
than  20  ounces  in  silver,  and  on  an  average  even  less.  A  good  idea  may  be 
gained  of  the  amount  of  silver  in  these  high-grade  lead-ores  by  referring  to  the 
ore  sales.  From  19  shipments  (or  between  900  and  icoo  tons)  of  ore  running  over 
50  per  cent  of  lead  by  assay,  the  average  was  but  15.03  ounces  per  ton,  or  0.0516 
per  cent,  of  silver.  When  this  ore  is  rich  it  occurs  in  pockets  in  the  poor  bodies, 
and  the  silver  is  always  visible  as  grains  and  scales  of  the  chlor-bromide. 

THE  IMPURE  CARBONATE  OF  LEAD. — The  pure  heavy  carbonate  of  lead  ore 
just  described  forms  a  large  part  of  the  ore  of  both  contacts.  The  more  impure 
ores  of  carbonate  of  lead  are  likewise  abundant.  These  may  consist  of  a  mixture 
of  pure  carbonate  of  lead  with  a  visible  gangue,  yet  too  finely  mixed  to  admit  of 
their  being  sloped  separately.  As  examples  of  this  class  we  have  streaks  of  cerus- 
site alternating  with  narrow  streaks  of  iron  oxide  or  sulphate,  or  some  siliceous 
gangue,  or  seams  of  it  running  up  into  and  mixing  with  the  porphyry.  But 
besides  these,  which  differ  in  no  way  from  the  large  bodies,  there  are  the  HARD 
CARBONATES  of  the  miner.  This  name  has  a  rather  broad  significance,  and  may 
be  used  to  indicate  any  sort  of  hard  rock  that  carries  silica  and  iron  sesquioxide, 
with  enough  carbonate  of  lead  and  silver  to  make  it  pay  as  ore. 

In  describing  the  siliceous  gangue  it  was  shown  that  lead  occurs  in  that 
material.  Whenever  the  percentage  of  lead  is  high,  20  to  30  per  cent,  we  have  a 
hard  carbonate.  A  perfect  series  of  such  material  is  found,  from  the  hard  jasper- 
like  rock  with  little  or  no  lead,  on  the  one  hand,  to  the  pure  lead  carbonates,  on 


THE  IMPURE  CARBONATE  OF  LEAD.  35 

the  other.  As  the  name  implies,  these  ores  are  hard.  The  ones  containing  much 
iron  and  silica  are  very  hard  and  scratch  glass  easily.  As  the  percentage  of  lead 
increases  they  become  softer,  but  are  always  hard  as  long  as  they  contain  any 
appreciable  amount  of  silica.  Excepting  the  poorest  of  them  they  are  perfectly 
homogeneous  in  texture  and  uniform  in  color.  The  color  varies  through  almost 
every  shade  of  brown,  red  and  gray. 

Hard  carbonates  do  not  occur  in  extensive  sheets  along  the  contact  like  other 
ores,  but  rather  as  thick,  massive  bodies  of  small  area  which  underlie  pure  car- 
bonate and  extend  down  into  waste.  When  the  percentage  of  lead  is  quite  high, 
say  40  per  cent  or  more,  there  are  frequently  streaks  or  veinlets  of  pure,  soft 
cerussite  running  through  it.  The  richest  variety  of  this  class  of  ore — that  is,  the 
richest  in  lead — is  of  a  light  gray  color  and  contains  little  iron.  It  is  extremely 
solid  and  heavy  and  will  contain  from  80  to  90  per  cent  of  carbonate  of  lead,  the 
remainder  being  mainly  silica.  Another  very  pure  variety  has  very  little  silica 
but  much  iron.  This  variety  is  deep  red  in  color  and  not  nearly  as  hard  as  the 
more  siliceous.  The  composition  of  such  an  ore  is  given  below  in  analysis  No.  i. 
For  the  other  analysis  I  am  indebted  to  Dr.  LeRoy  W.  McCay  of  the  Scientific 
School,  Princeton.  It  shows  the  composition  of  a  fair  average  specimen  of  hard 
carbonate  in  all  but  the  silver.  The  latter  metal  is  present  far  in  excess  of  the 

average. 

(i)  (a) 

Silica 2.82  18.84 

Silver  chloride 0.16  1.30 

Lead  oxide 66.98  54.89 

Iron  sesquioxide I4-23  11.38 

Lime trace  i.  78 

Carbonic  acid i3-°7  10.83 

Sulphur  trioxide °-55 

Water..                                                                  1.52  1.61 


99.33          100.65 

No.  2  is  deep  brownish-red  in  color  and  very  hard.  It  has  a  perfect  jointed 
structure  which  divides  the  rock  into  small  rectangular  blocks.  Though  this 
jointed  structure  is  very  common,  it  is  seldom  as  perfect  as  this.  It  is  on  these 
joints  that  the  cerargyrite  which  makes  the  ore  so  rich  occurs. 

Several  thousand  tons  of  such  ores  have  been  taken  out  by  the  present  man 
agement,  much  of  which  was  stored  in  old  cribs  and  drifts,  and  the  rest  in  place 
through  the  old  works  of  the  former  company.  In  some  cases  almost  the  entire 
filling  of  an  old  drift  would  be  shipped  as  ore,  after  passing  through  the  hands  of 
the  ore-sorters,  and  would  realize  as  much  as  $20  to  $30  a  ton  above  all  expenses. 

The  average  amount  of  silver  in  these  ores  is  much  larger  in  proportion  to 
the  amount  of  lead  present  than  it  is  in  the  pure  cerussites.  It  is  seldom  that  a 
hard  carbonate  assaying  30  or  40  per  cent  of  lead  carries  less  than  as  many  ounces 


36  OCCURRENCE  OF    THE  ORES. 

of  silver.  A  large  amount  of  the  silver  ore  has  often  been  deposited  along  the 
crevices  in.it  by  percolating  waters.  Such  is  generally  visible  in  scales. 

The  question  now  arises  as  to  the  source  of  the  carbonate  of  lead  in  these 
siliceous  ores.  That  the  water  dissolves  some  lead  and  redeposits  it  below  admits 
of  no  doubt,  for  the  incrustations  of  cerussite  along  joints  and  cleavage  planes  are 
very  common.  But  it  cannot  be  supposed  that  this  solution  and  redeposition  has 
been  so  extensive  as  to  account  for  much  more  than  a  trace  of  the  lead  in  the 
hard  carbonates.  The  only  way  they  can  have  arisen  is  by  the  oxidation  of 
impure  galenas.  A  perfect  and  complete  series  of  these  ores,  from  impure  ones 
not  assaying  over  20  per  cent  to  the  purest  gray  varieties  running  60  to  65  per 
cent  lead,  was  collected,  all  of  which  contain  bright  particles  of  galena  undergo- 
ing decomposition.  In  all  of  these  the  various  stages  between  the  undecomposed 
galena  and  the  thoroughly  oxidized  carbonate  may  be  seen.  It  cannot  be  doubted 
that  these  hard  carbonates  have  arisen  from  impure  masses  of  galena  just  as  the 
more  pure  carbonates  of  lead  have  arisen  from  bodies  of  more  pure  galena. 

THE  BASIC  IRON  SULPHATE. — The  most  peculiar  material  in  the  mines  is  the 
hydrous  basic  ferric  sulphate  which  so  frequently  underlies  the  lead-ore  in  both 
the  upper  and  lower  workings.  Though  this  substance  is  only  sometimes  very 
fine  ore,  it  is  grouped  with  the  ores  because  it  is  often  rich  and  always  contains 
some  lead  and  silver.  It  forms  sheets  which,  with  remarkable  persistence,  extend 
beneath  the  cerussite  ores  in  certain  parts  of  the  mines.  Its  position  is  shown  in 
sections  i  and  2,  Plate  I,  and  is  represented  by  the  yellow  color.  In  color  it  is  a 
pure  light-yellow  ochre  and  has  a  great  resemblance  to  yellow  clay.  It  is  never 
plastic  except  when  wet.  Usually  it  is  dry  and  firm  and  has  a  perfect  jointed 
structure,  due  probably  to  pressure.  It  consists  of  iron  sesquioxide  combined 
with  sulphuric  acid,  has  much  water  and  varying  amounts  of  sulphate  of  lead. 
When  subjected  to  intense  heat  it  loses  all  its  water  and  most  of  its  sulphuric 
acid  combined  with  the  iron.  The  following  is  an  analysis  of  a  specimen  of  this 
material : 

Lead  sulphate ; 29. 18 

Silica trace 

Iron  sesquioxide 40. 22 

Alumina HI 

Sulphur  trioxide 18.02 

Water II.2O 

Silver  chloride 0.27 

100.00 

This  sample  contains  more  lead  sulphate  than  the  average.  The  percentage 
of  lead  being  low,  the  value  of  this  material  depends  largely  on  the  amount  of 
silver  it  contains.  In  the  Upper  Waterloo  large  bodies  of  it  occur  under  the  pure 
lead  ore  which  contain  on  an  average  only  a  few  ounces,  and  are  therefore  too 


THE  CHLORIDE  OF  SILVER.  37 

poor  to  mine.  In  the  upper  contact  this  substance  is  rarely  rich,  except  when  it 
contains  chloride  of  silver  in  visible  form.  In  the  Lower  Waterloo  and  Forsaken 
it  is  abundant  in  certain  places,  chiefly  under  the  cerussite  ore  of  the  branch  cur- 
rent. Here  it  always  runs  well  in  silver  (from  20  to  100  ounces),  and  makes  an 
excellent  ore.  The  silver  is  never  visible  in  this  body.  It  has  most  probably 
arisen  from  the  galena,  which  has  given  rise  to  the  sulphate. 

The  fact  that  this  material,  wherever  it  occurs,  is  always  perfectly  pure,  well- 
defined  and  abruptly  bounded  by  the  other  vein-material  indicates  without  a 
doubt  that  it  has  all  arisen  in  the  same  way,  and  differently  from  any  of  the  rest 
of  the  vein-material  about  it.  Although  the  soft  black  iron  which  often  lies  below 
both  this  and  the  other  ores  contains  some  sulphuric  acid,  this  is  not  often  in 
large  quantity  and  some  of  the  iron  contains  none.  Moreover,  the  iron  contains 
no  lead  and,  even  when  under  very  rich  ore,  not  enough  silver  to  pay. 

The  manner  in  which  it  is  believed  to  have  been  formed  has  already  been 
stated  ;  namely,  by  the  oxidation  of  a  belt  of  pyrites  mixed  with  more  or  less  galena 
(seldom  over  15  or  20  per  cent)  which  formerly  occupied  this  position  and  formed 
a  layer  with  the  more  pure  galena  above  it.  This  easily  oxidized  mineral,  sub- 
jected for  a  great  length  of  time  to  agencies  which  have  almost  completely 
oxidized  the  last  traces  of  galena  in  the  ore  above  it,  has  completely  succumbed 
and  been  brought  to  its  highest  state  of  oxidation.  Not  a  trace  of  pyrites  has 
ever  been  seen  in  it.  Small  nodules  of  galena  of  great  richness  in  silver  have 
occasionally  been  found  in  it.  These  nodules  assay  from  60  to  70  per  cent  in 
lead  and  average  as  high  as  450  to  500  oz.  in  silver.  They  are  seldom  entirely 
bright  at  the  centre,  but  even  there  have  begun  to  decompose  along  the  cleavage 
planes. 

THE  CHLORIDE  OF  SILVER. — The  great  difference  in  silver  contents  between 
the  carbonate  of  lead  and  the  galena  is  very  striking.  The  amount  of  silver  in  a 
thoroughly  oxidized  carbonate  of  lead  is  never  normally  above  40  or  50  ounces. 
Even  when  no  richer  than  this  the  silver  may  often  be  seen  as  tiny  grains  and 
scales  of  chloride  scattered  among  the  granules.  The  average  richness  of  the 
carbonate  of  lead  has  already  been  shown  to  be  much  less  than  this. 

The  galena,  on  the  other  hand,  is  (as  has  already  been  stated)  much  richer 
and  averages  at  least  the  half  of  one  per  cent  silver.  From  ten  samples  of  ore 
assayed,  five  of  bright  large  galena  nodules  and  five  of  the  .thoroughly  oxidized 
carbonate  of  lead  around  them,  it  was  found  that  in  proportion  to  the  lead  present 
in  each  there  was  over  six  times  as  much  silver  in  the  galenas  as  in  the  cerussites. 

It  is  easy  to  explain  where  the  silver  missing  from  the  carbonates  has  gone. 
All  the  iron  about  the  ore-bodies  contains  silver.  All  the  porphyry  along  the 
contact  contains  it.  And  it  is  not  merely  the  material  about  the  ore.  The  lime- 
stone and  the  vein-matter  deep  down  in  the  current  often  contain  traces  of  silver. 


38  OCCURRENCE  OF   THE  ORES. 

Assays  of  these  materials  yield  from  one  to  four  ounces.  Scarcely  any  vein-mat- 
ter can  be  obtained  that  does  not  run  one  or  two  ounces,  and  much  of  it  runs 
higher.  In  some  places  the  amount  of  silver  deposited  is  much  more  considerable 
and  then  ores  arise,  it  may  be  out  of  what  before  was  far  too  poor  to  be  such.  In 
these  ores  the  silver-bearing  mineral  can  always  be  recognized.  In  both  mines  it 
is  invariably  the  same  in  color,  light  greenish  yellow.  It  is  soft  and  sectile,  and 
feels  like  lead  between  the  teeth.  Exposed  to  the  light  it  does  not  change  color 
in  the  least.  Qualitative  tests  show  it  to  contain  chlorine,  bromine  and  iodine,  all 
in  considerable  quantity.  It  occurs  as  scales  or  plates  and  as  single  crystalline 
grains,  or  aggregates  of  such  grains,  and  as  rough  crystalline  coatings  on  the 
walls  of  crevices  and  joints  in  the  various  vein-materials ;  also  as  scales  and  grains 
more  or  less  thickly  scattered  through  granular  carbonate  of  lead,  and  as  highly 
crystalline  lumps  forming  the  lining  of  druses  and  hollows  in  that  mineral,  just  as 
cerussite  crystallizes  in  the  hollow  gafena  nodules.  Though  generally  highly 
crystalline,  the  grains  are  small  and  have  to  be  examined  with  a  magnifying-glass. 

The  most  common  ore  formed  by  the  deposition  of  cerargyrite  is  low-grade 
and  siliceous.  It  is  the  hard,  siliceous  gangue,  with  numerous  joints  and  crevices 
which,  interlacing  and  extending  all  through  the  rock,  allow  the  mine-waters  to 
trickle  through  them  or  stand  in  them.  The  chloride  is  deposited  along  these 
joints.  As  long  as  this  is  visible  it  is  sloped  down  and  sent  to  the  surface,  where 
it  is  carefully  sorted.  Of  course  this  is  not  done  when  the  base  itself  is  pay-ore. 
Chloride  seldom  enriches  the  iron  sufficiently  to  make  it  pay.  When  the  yellow 
sulphate  of  iron  is  firm  and  has  crevices  running  through  it,  it  also  frequently 
shows  chloride  of  silver.  The  pure  carbonates  of  lead  frequently  have  it,  and  it 
has  occasionally  been  found  in  lumps  of  decomposing  galena. 

The  most  remarkable  deposit  of  ore  arising  from  the  deposition  of  cerargy- 
rite occurs  in  the  White  porphyry  on  the  Evening  Star.  This  body  was  struck 
by  the  main  shaft  between  20  and  30  feet  above  the  contact.  The  gangue  is  noth- 
ing but  porphyry.  This  is  in  a  state  of  extreme  decomposition  here,  and  there  is  a 
deep  stain  of  iron  oxide  along  all  the  joints  which  divide  the  rock  into  lumps  of 
but  a  few  inches  in  diameter.  The  silver  is  mostly  invisible,  but  shows  here  and 
there  through  the  stained  portion  as  tiny  specks  of  chloride.  The  amount  of  lead 
present  is  very  low  and  it  is  often  altogether  wanting.  This  body  is  very  irregular, 
but  in  many  places  it  is  8  or  10  feet  thick  and  three  or  four  times  as  broad.  The 
ore  could  only  be  distinguished  from  the  waste  by  assay.  Just  below  this  point  a 
large  dike  of  Gray  porphyry  has  broken  up  and  reaches  almost  to  the  White. 
It  seems  not  improbable  that  the  disturbances  accompanying  this  eruption  may 
have  shattered  the  White  porphyry  and  allowed  the  solutions  bearing  the  metals 
a  limited  access  to  this  rock. 

Rich  pockets  of  ore  always  owe  their  richness  to  the  chloride  of  silver  that 


THE    UPPER   CURRENT.  39 

has  been  concentrated  there.  They  generally  occur  in  the  pure  carbonate  of 
lead.  Specimens  of  the  latter  metal  are  frequently  found,  which  run  from  5  to  10 
per  cent  of  silver,  but  there  is  seldom  over  a  few  pounds  of  such  ore  found  at  one 
place.  Lumps  of  this  cerargyrite  weighing  a  few  ounces  have  frequently  been 
met  with.  Only  one  or  two  lumps  weighing  over  a  pound  have  ever  been  found. 
Such  pockets  are  always  small,  and  it  is  rarely  that  many  tons  of  ore  averaging 
over  loo  ounces  are  found  at  one  place. 


THE  ORES   IN   POSITION. 

There  has  been  so  much  ore  removed  from  the  current  under  the  White 
porphyry  that  it  is  difficult  to  give  a  good  idea  of  the  ore  in  the  current  taken  as 
a  whole.  Its  thickness  in  different  parts  and  its  richness  may  be  shown  from  the 
size  of  the  stopes  and  their  thickness,  from  the  appearance  of  the  streaks  of  ore 
found  in  the  old  workings  and  by  referring  to  the  ore  sales,  but  with  regard  to  the 
ores  forming  the  different  parts  of  the  body,  their  relative  size  and  their  position 
very  little  information  can  be  given.  Under  the  Gray  porphyry  as  clear  a  view 
as  could  be  desired  is  obtained  of  the  ores  standing,  in  all  parts  of  the  current. 

THE  UPPER  CURRENT. 

This  current  reached  its  greatest  thickness  in  the  Evening  Star.  The  thick- 
ness of  the  ore  at  the  centre  of  the  current  was,  as  already  stated,  very  great.  At 
the  centre  and  north-western  side  the  ore  varied  from  30  to  60  feet  in  thickness 
and  contained  so  little  waste  that  there  was  often  great  trouble  in  getting  material 
with  which  to  fill  the  cribs.  From  the  centre  the  ore  rapidly  thinned  towards 
the  south-eastern  side,  till  at  the  upper  shaft  it  was  very  thin,  and  a  little  beyond 
it  ceased  altogether.  The  bottom  of  the  ore-body  was  extremely  irregular  and 
ended  in  a  series  of  branchlets,  streaks  and  isolated  bodies  running  through  or 
lying  in  the  gangue  below.  Much  of  the  ore  at  the  bottom  was  very  siliceous, 
hard  carbonate  of  lead ;  some  of  it  low-grade  ore  consisting  of  iron  impregnated 
with  cerargyrite.  The  top  of  the  current  was  more  regular,  being  against  the 
porphyry.  It  must  not  be  thought  that  the  porphyry  was  a  perfectly  smooth 
sheet.  On  the  contrary,  it  was  very  irregular,  but  the  irregularities  were  all 
local.  The  sheet  taken  as  a  whole  is  smooth  enough,  but  it  has  innumerable 
hollows  and  gashes,  many  of  them  of  considerable  size.  These  were  generally 
filled  with  ore  or  silica. 

The  quality  of  the  Evening  Star  ores  is  shown  by  the  sales  to  have  been  very 
fine.  The  percentage  of  lead  is  low  when  compared  with  the  Morning  Star  ores ; 


40  .  OCCURRENCE  OF   THE  ORES. 

but  in  silver  they  run  much  higher.  In  Part  II.,  a  table  is  given  showing  the  pro- 
duction of  ore  for  both  mines  and  their  average  richness  for  August,  September 
and  October  1882.  This  table  shows  the  stated  differences  very  plainly.  The 
average  of  the  Evening  Star  for  the  year  before  would  have  been  considerably 
higher  in  both  silver  and  lead.  The  silver  for  that  time  averaged  from  50  to  60 
oz.  per  ton ;  the  lead  was  still  far  lower  than  the  average  in  the  Morning  Star 
portion  of  the  same  current,  which  is  also  higher  in  lead  than  the  average  of  the 
Lower  Waterloo  ores.  In  the  Evening  Star  the  top  of  the  main  body  was  richer 
than  the  bottom,  especially  in  lead. 

The  ore-body  thinned  as  it  approached  the  Morning  Star  boundary,  and 
entered  that  claim  a  much  thinner  body,  though  the  area  occupied  by  ore  was 
just  as  large.  In  some  places  along  the  centre  it  was  still  very  thick,  sometimes 
20  or  30  feet.  At  other  places  along  the  sides  of  the  current  some  barren  spots 
occurred,  but  the  continuity  of  the  ore  was  never  broken.  The  percentage  of 
lead  in  the  ores  begins  to  increase  and  the  silver,  though  still  high,  begins  to 
decrease  in  amount.  The  ground  in  this  part  of  the  property  was  stoped  by  the 
old  Company  ;  but  the  nature  of  the  ores  can  be  inferred  from  the  streaks  over- 
looked which  are  every  now  and  then  discovered.  There  seems  to  have  been 
along  the  contact  some  very  pure  carbonate  of  lead  which  ran  very  well  in  silver, 
from  25  1040  oz.  The  contact  was  very  irregular  and  had  along  it  much  spongy 
silica,  some  of  which  was  quite  pure  and  some  mixed  with  ore.  Below  the  pure 
streak  of  "sand"  carbonate  there  was  much  very  highly  siliceous  ore  containing 
scarcely  a  trace  of  iron.  The  ore  passed  on  towards  the  Upper  Waterloo  shaft, 
No.  i,  Plate  II,  where  there  was  very  pure  cerussite  along  the  contact  and  a 
great  deal  of  hard  carbonate,  now  often  containing  iron,  below.  More  of  this 
hard  ore  occurred  in  this  part  of  the  property  than  any  where  else  in  either  mine. 
Beyond  this  the  rest  of  the  current  was  still  standing  last  fall.  The  hard  car- 
bonates cease  and  streaks  of  basic  sulphate  of  iron  begin  to  appear  under  the  ore 
just  beyond  the  last-mentioned  shaft.  The  pay-streak  was  weak  at  first,  but 
rapidly  strengthened  and  developed  into  a  fine  body  of  large  area  of  which 
section  i,  Plate  I,  is  typical.  The  blue  of  this  section  shows  the  lead-ore,  which 
assays  from  68  to  75  per  cent  lead  and  averages  as  high  as  70  to  72  per  cent.  It 
lies  immediately  below  the  porphyry.  The  section  shows  neither  the  thinnest 
nor  the  thickest  part  of  the  body,  but  represents  a  fair  average.  The  yellow 
band  represents  the  yellow  sulphate  of  iron.  This  material  contains,  intimately 
mixed  with  it,  from  10  to  30  per  cent  of  anglesite,  and  sometimes  a  little  car- 
bonate of  lead.  In  silver  it  generally  runs  from  4  to  6  oz.  In  section  i  this 
material  is  seen  to  reach  the  contact  at  one  place,  cutting  off  the  cerussite.  It 
runs  on  beyond  this  point  for  30  or  40  feet,  maintaining  a  thickness  of  loto  14  feet, 
and  then  thins  out  and  disappears,  ordinary  iron  taking  its  place.  These  sul- 


THE  LOWER   CURRENT.  41 

phates,  being  of  so  low  a  grade,  are  left  in  the  mine  as  waste,  or  if  they  have  to  be 
removed  they  are  sent  up  for  the  dressing  dump. 

This  body  of  ore,  though  of  so  low  a  grade  in  silver,  is  remarkable  for  the 
rich  pockets  that  occur  in  it.  These  are  both  large  and  small.  The  small  ones 
often  contain  little  nuggets  of  chloride  of  silver.  There  are  only  one  or  two  of 
the  larger  pockets,  and  they  do  not  contain  excessively  rich  ore.  They  are  from 
20  to  30  feet  through  each  way,  and  vary  from  50  to  300  ounces  in  silver,  with  an 
average  of  75  to  100  ounces.  The  yellow  sulphate  below  these  pockets  is  also 
pay-ore.  Whether  this  rich  ore  has  arisen  from  a  concentration  of  the  silver 
from  the  poorer  ores  around  it,  or  whether  it  comes  from  galena  richer  than  the 
rest,  it  is  hard  to  decide.  The  fact  that  in  the  Lower  Waterloo  galena  samples 
taken  from  the  same  drift,  and  from  what  was  once  the  same  body,  differ  greatly 
in  their  silver  contents  shows  that  the  last  is  certainly  possible. 

Before  leaving  this  current  it  may  be  worth  while  to  describe  a  dike  of  Gray 
porphyry  which  breaks  up  in  this  part  of  the  mine  on  the  northern  side  of  the 
current.  This  dike  rises  to  the  contact  and  spreads  out  along  it.  The  ore  thins 
as  it  approaches  it  and  ends,  at  some  places,  in  direct  contact  with  it.  The  only 
drift  that  cuts  through  this  dike  shows  it  to  rise  up  with  a  thickness  of  8  or  10 
feet  at  this  point.  It  lies  in  a  sheet  along  the  White  porphyry  above,  in  some 
places  30  or  40  feet  wide.  At  the  western  end  an  upraise  shows  it  to  have  a  thick- 
ness of  about  25  feet.  No  ores  were  found  beyond  this  dike,  but  when  the  drift 
stopped  there  was  limestone  in  the  face  of  it.  The  dike  showed  the  character- 
istic structure  of  the  Gray  porphyry.  It  was  in  a  highly  decomposed  condition, 
soft  and  changing  into  clay  just  as  the  decomposition  goes  on  in  the  lower  work- 
ings. All  about  it  the  White  porphyry  decomposes  to  the  dry  siliceous  product, 
often  showing  specks  of  white  mica  which  has  been  so  frequently  mentioned. 

THE  LOWER  CURRENT. 

The  smaller  branch  current  under  the  Gray  porphyry  begins  at  the  lower 
north-west  corner  of  the  Evening  Star  claim,  and  runs  with  a  north-easterly 
course  till  it  joins  the  larger  one.  The  area  occupied  by  pay-ore  in  this  current 
is  remarkably  large,  though  the  ore  is  never  very  thick,  being  seldom  more  than 
six  or  less  than  two  feet  through. 

In  the  Evening  Star  there"  is  very  little  carbonate  of  lead.  Almost  all  the  ore 
is  the  basic  sulphate  of  iron  mixed  with  anglesite.  The  carbonate  of  lead  is  not 
continuous,  but  occurs  in  narrow  pure  streaks  of  small  extent,  generally  along  the 
contact  and  always  underlaid  by  the  other  ore.  Sometimes  small  lenticular 
strips  of  carbonate  of  lead  occur  imbedded  in  the  sulphates  but  parallel  to  the 
contact.  The  thickness  of  the  pay-ore  in  this  part  of  the  current  is  variable. 


42  OCCURRENCE  OF   THE  ORES. 

Four  feet  is  a  good  average.  Along  the  sides  of  the  current  the  ore  is  very 
irregular  and  ends  in  deep  gashes  running  into  the  waste,  from  which  it  is  easily 
distinguished  by  the  color.  Below  the  ore  there  is  sometimes  much  ferro-siliceous 
gangue,  very  hard,  but  more  commonly  only  the  black  iron-ore. 

After  passing  the  Morning  Star  line  the  ore  in  the  current  weakens  some- 
what and,  along  the  lower  south-eastern  side  especially,  is  very  thin.  At  the  same 
time  the  carbonate  of  lead  becomes  relatively  more  abundant,  until  at  about  a  line 
drawn  across  the  current  through  the  Old  Forsaken  shaft,  No.  8,  Plate  II,  there  is 
a  continuous  seam  of  "  sand  "  over  one  of  the  yellow  ore.  Though  here  only  a 
foot  thick,  the  two  bands  are  remarkably  well  separated  from  one  another, 
as  analysis  No.  (2),  page  34,  and  that  on  page  36  show  very  well.  The  two  speci- 
mens from  which  the  analyses  were  made  lay  within  six  inches  of  each  other  in 
the  mine,  and  were  both  taken  from  a  specimen  of  only  a  few  pounds'  weight,  of 
which  the  lower  half  was  the  sulphate  and  the  upper  the  carbonate. 

From  this  point  the  ore  begins  to  thicken  and  rapidly  develops  into  a  fine 
body  which  extends  without  change  almost  to  the  Old  Waterloo  shaft.  This 
body  has  a  continuous  streak  of  lead  carbonate  above  it,  and  one  of  the  yellow  ore 
below.  On  the  north-west  side  of  the  current  the  ore  is  the  strongest  all  the  way 
along,  and  the  carbonate  of  lead  streak  is  thinner  than  the  sulphate,  the  ratio 
being  about  i  :  2.  On  the  lower  south-eastern  side  the  pay-streak  is  not  so  strong, 
and  the  carbonate  of  lead  is  relatively  much  thicker.  Section  2,  Plate  I,  shows  a 
section  of  this  body  running  along  the  centre  of  the  current.  The  carbonate  of 
lead  streak  is  seen  to  be  very  much  the  thicker  of  the  two  here,  but  further  up 
towards  the  north-western  side  this  is  not  the  case.  . 

Above  this  body  of  ore  there  is  a  siliceous  sheet,  soft,  loose  and  resembling 
moist  sand  more  than  anything  else.  Further  from  the  ore  it  is  harder,  and  has  a 
jointed  structure  which  divides  it  into  small,  angular  blocks  but  a  few  inches  in 
thickness.  This  firmer  material  resembles  a  softened  and  disintegrated  quartzite. 
It  varies  from  2  to  10  feet  in  thickness,  and  when  penetrated  soft  Gray  porphyry 
is  found  beyond.  The  lead  carbonate  mixes  with  this  sandy  material.  At  the 
bottom  of  the  streak  it  is  as  a  rule  pure,  as  shown  by  the  analysis,  page  34. 
Towards  the  top  it  gradually  becomes  more  impure  and  merges  into  this  soft 
siliceous  layer,  so  that  in  most  cases  no  boundary  can  be  distinguished. 

Though  averaging  much  lower  in  lead  than  the  Upper  Waterloo  ores,  the 
carbonate  of  lead  is  richer  in  silver  in  proportion  to  its  lead  contents.  It  assays 
from  15  to  30  ounces  in  silver  and  from  30  to  50  per  cent  of  lead.  Below  this 
streak  the  yellow  sulphate  is  very  pure  and  always  good  ore.  It  is  low  in  lead, 
but  is  richer  in  silver  than  the  carbonate.  Assays  show  it  to  vary  greatly  in 
value.  From  20  to  80  ounces  per  ton  in  silver  and  from  i  to  20  per  cent  in  lead 
are  the  usual  amounts  of  these  metals  in  this  ore ;  the  average  is  from  40  to  50 


THE  LOWER   CURRENT.  43 

ounces  and  from  5  to  15  per  cent.  Most  silver  is  found,  as  a  rule,  where  there  is 
most  sulphate  of  lead,  though  this  is  not  always  the  case.  No  specimen  showing 
visible  chloride  was  ever  observed  in  this  current. 

This  ore-body  begins  to  diminish  in  breadth  and  thickness  about  50  feet 
before  the  Old  Waterloo  is  reached.  The  yellow  ore  diminishes  most  rapidly 
and  opposite  this  shaft  appears  only  in  isolated  patches,  mostly  below,  sometimes 
above,  the  carbonate  of  lead.  Up  to  this  point  the  dip  of  the  Gray  porphyry  has 
been  quite  gradual,  but  here  the  line  is  reached  where  the  entire  sheet  assumes  a 
much  steeper  dip  (from  30°  to  35°).  The  crest  of  this  bend  is  marked  by  the 
Lower  and  Old  Waterloo  shafts,  both  of  which  are  situated  upon  it.  The  ore 
passes  over  this  bend  and  still  continues  a  pay-streak,  though  much  changed  in 
nature.  Both  the  siliceous  sheet  above  and  the  sulphate  below  have  disappeared, 
and  the  ore  now  consists  of  narrow  streaks  of  granular  carbonate  of  lead,  with  a 
great  deal  of  highly  siliceous  and  very  hard  ore  below — so  hard  that  it  barely 
pays  to  mine  it,  although  it  yields  $10  to  $15  net  per  ton  from  the  smelter. 

The  other  branch  current  and  the  main  current  below  their  juncture  are  very 
different.  The  ores  of  the  northern  branch  current  are  principally  galenas. 
They  do  not  occur  in  large,  continuous  bodies  as  do  the  ores  in  all  other  places, 
but  form  a  series  or  string  of  small  bodies  which  are,  however,  very  rich.  The 
ore  in  this  part  of  the  mine  overlies  black  iron-ore  except  in  the  case  of  a  single 
pocket  of  large  size,  where  a  seam  of  yellow  ore,  very  thin  but  exceedingly  rich, 
occurred.  Above  the  lower  shaft,  No.  6,  where  the  dip  is  not  so  great,  the  ore  is 
in  larger  bodies  than  just  after  the  steep  dip  is  begun.  At  one  place  the  ore 
occurred  as  small  irregular  seams  of  galena,  seldom  as  much  as  a  foot  thick, 
scattered  along  the  contact,  and  in  black  iron-ore  through  a  zone  reaching  6  to  8 
feet  from  the  porphyry.  Everything  has  to  be  stoped  in  such  a  body,  and  the 
galena  separated  from  the  iron  by  careful  sorting.  The  largest  of  these  bodies 
always  contains  much  carbonate  of  lead,  as  already  sufficiently  mentioned  under 
the  head  of  Galenas. 

Below  the  juncture  of  the  two  currents  the  ore-bodies  are  larger  and"  more 
completely  oxidized.  They  also  run  much  less  in  silver  than  the  galenas.  Section 
3,  Plate  I,  is  taken  along  the  strike  through  the  ore  in  this  part  of  the  mine.  It  is 
at  a  point  only  a  short  distance  below  the  juncture  of  the  smaller  current.  It 
consists  of  a  low-grade  carbonate  of  lead  of  average  quality  in  silver.  The 
impurities,  which  are  abundant,  are  mainly  ferruginous.  Galena  occurs  only  as 
nodules,  and  now  forms  but  a  small  portion  of  its  bulk.  This  body  begins  about 
75  feet  from  the  Henrietta  line  and  extends  southward  to  the  other  side  of  the 
current.  Toward  the  east  it  stops  suddenly  on  the  crest  of  a  very  steep  dip 
taken  by  the  porphyry  at  an  angle  of  at  least  70°.  It  continues  at  this  rate  for 
about  20  feet,  and  then  resumes  its  regular  dip.  The  ore  begins  again  30  or  40 


44  OCCURRENCE  OF   THE  ORES. 

feet  beyond,  and  has  continued  from  this  point  on  as  far  as  exploration  has  been 
pushed,  a  distance  of  about  ico  feet.  The  grade  of  the  ore  has  improved  a  little 
also,  and  the  average  of  silver  is  higher  than  has  been  struck  anywhere  else  in  the 
current  except  in  the  galena  ores  already  mentioned. 

The  difference  between  the  degree  of  oxidation  of  the  two  branches  is  very 
striking.  The  fact  that  the  ores  of  the  one  are  completely  oxidized  while  those 
of  the  other  are  not  nearly  so,  and  that  below  the  junction  the  ores,  though 
further  from  the  surface,  are  more  completely  oxidized  than  the  ores  in  the  large 
branch,  shows  undoubtedly  that  the  smaller  current  has  for  some  reason  been  the 
course  of  greater  quantities  of  meteoric  waters.  As  'the  smaller  current  cuts 
across  the  dip  of  the  stratum  and  makes  a  sharp  angle  with  the  outcrop,  all  the 
waters  entering  at  the  outcrop  and  following  the  contact  between  the  outcrop  of 
the  current  and  its  junction  with  the  main  channel  would  go  down  to  it,  while  the 
other  current,  being  perpendicular  to  the  outcrop  'and  following  the  dip  of  the 
porphyry,  would  be  the  recipient  of  comparatively  little.  That  water  did  pass 
along  both  currents  many  channels  washed  out  along  the  contact  prove. 


THE  DEPOSITION  OF  THE  VEIN-MATERIALS. 

There  can  be  little  doubt  as  to  the  way  in  which  the  vein-matter  was 
deposited.  The  evidence  tending  to  show  that  "  the  process  of  deposition  of  the 
vein-materials  was  a  chemical  interchange,  or  actual  replacement  of  the  rock  mass  in 
which  they  were  deposited"  seems  the  more  indisputable  the  more  one  sees  of  the 
deposits.  The  great  changes  due  to  extreme  oxidation  and  the  action  of  large 
quantities  of  surface-waters  for  such  a  long  period  of  time  render  it  impossible  to 
trace  step  by  step  the  way  in  which  the  replacement  was  accomplished,  but  that 
it  did  take  place  there  is  sufficient  proof. 

During  September  and  October,  1882,  the  upper  shaft  of  the  Evening  Star 
was  sunk,  from  8  feet  below  the  contact,  100  feet  towards  the  Gray  porphyry 
sheet.  It  was  mentioned  above  that  this  shaft  strikes  the  south-eastern  edge 
of  the  main  upper  current.  The  ore  here  was  not  very  thick,  much  of  the  area 
had  no  pay-ore,  but  there  was  from  4  to  8  feet  of  vein-matter  along  the  contact 
about  the  shaft.  On  sinking  the  shaft,  limestone  was  entered  at  the  very  start; 
namely,  at  8  feet  below  the  porphyry.  It  was  stained  and  much  altered,  coarse- 
grained but  firm,  although  not  nearly  as  solid  as  the  normal  blue  limestone.  This 
limestone  continued  only  10  feet,  and  at  18  feet  below  the  contact  iron  was  again 
entered.  Both  the  upper  and  lower  sides  of  the  limestone  layer  were  parallel  to 
the  dip  of  the  formation,  and  the  bedding-planes,  which  were  well  marked,  were 
likewise  parallel  to  it.  The  iron  below  was  of  the  common  soft  variety  and  con- 


THE  DEPOSITION  OF   THE  VEIN-MATERIALS.  45 

tained  sulphates.  It  had  no  limestone  in  it.  This  streak  lasted  but  7  feet,  and  like 
all  the  others,  above  and  below,  was  parallel  to  the  dip  of  the  formation.  Lime- 
stone was  again  entered  at  25  feet  below  the  contact.  This  layer  was  so  softened 
and  disintegrated  that  it  had  lost  all  coherency  and  was  very  loose  and  crumbly. 
The  bedding-planes  were  completely  obliterated.  It  is  met  with  in  other  parts  of 
the  mine,  and  the  miners  have  the  special  name  "lime-sand"  for  it.  At  35  feet 
another  layer  of  iron  appeared,  and  continued  without  interruption  for  over  40 
feet.  This  iron  was  firmer  than  the  other  layer,  but  still  contained  some  sulphuric 
acid.  At  about  50  feet  it  contained  from  5  to  20  per  cent  of  lead,  and  here  and 
there  nodules  of  galena  poor  in  silver.  This  lead  bearing  material  occupied  a 
zone  parallel  to  the  dip  of  the  beds.  At  about  80  feet  "  boulders"  of  limestone 
began  to  appear,  imbedded  in  the  vein-matter.  These  isolated  lumps  showed, 
when  large,  the  bedding-planes  in  position  and  having  the  regular  dip.  They 
became  more  and  more  frequent,  until  at  100  feet  solid  limestone  was  reached, 
the  purest  struck  anywhere  on  either  mine.  At  this  depth  the  sinking  was 
temporarily  stopped. 

It  would  be  hard  to  account  for  these  layers  of  limestone  and  "  boulders"  all 
in  position  if  a  pre-existing  cave  were  assumed.  They  can  only  be  satisfactorily 
accounted  for  by  supposing  the  iron  to  be  in  the  position  of  former  layers  of  lime- 
stone, which  allowed  an  easier  passage  for  the  flowing  waters,  and  that  along 
these  courses  the  vein-matter  was  deposited  by  replacement. 

All  the  iron  which  lies  near  the  ores  or  along  evident  water-courses,  although 
containing  much  more  iron  and  manganese  as  oxides,  has  always  a  considerable 
though  variable  amount  of  basic  sulphates.  The  yellow  ore  which  underlies  the 
lead  carbonates  in  some  places,  and  which  is  supposed  to  have  been  formerly  iron 
pyrites  with  a  little  galena,  consists,  as  has  been  already  stated,  altogether  of 
basic  sulphate.  It  would  seem  that  if  the  conditions,  when  these  sulphides  were 
decomposing,  favored  the  formation  of  basic  sulphates,  the  latter  compounds  would 
have  existed  in  large  quantity  in  the  iron  lower  down,  provided  this  had  formerly 
consisted  of  the  sulphides  of  iron  and  manganese.  The  analysis  given  on  page  27 
shows  that  the  more  pure  variety  of  iron  is  almost  free  from  sulphur.  The  main 
mass  of  the  vein-matter,  in  fact,  contains  little  of  this  element.  Further,  although  the 
iron  often  reaches  a  thickness  of  60  to  100  feet,  a  trace  of  pyrites  has  in  no  case  been 
discovered  in  it.  It  seems  more  probable,  therefore,  that  the  iron  and  manganese 
were  deposited  by  the  ordinary  reactions  between  mineralized  waters  and  lime- 
stone, the  solution  depositing  its  protoxides  of  iron  and  manganese  and  replacing 
them  by  calcium  and  magnesium  oxides.  The  iron  and  manganese  now  forming 
the  main  body  of  the  currents  would  accordingly  have  been  deposited  as  the  car- 
bonates. From  these  the  hydrous  oxides  as  they  now  exist  would  be  formed  by 
the  oxidizing  waters.  The  silica  must  have  been  deposited  by  the  replacement  of 


46  OCCURRENCE  OF   THE  ORES. 

limestone  by  that  substance,  molecule  for  molecule.  That  the  lead  and  silver  and 
some  of  the  iron  were  deposited  as  the  sulphides  there  can  be  no  doubt.  The 
proofs  of  this  have,  however,  been  given  under  the  description  of  the  different 
ores. 

SOURCE  OF  THE  VEIN-MATERIAL. — As  to  the  source  of  the  vein-material, 
no  careful  study  of  the  question  was  attempted,  as  neither  time  nor  data  could  be 
found.  The  White  porphyry,  of  which  an  analysis  is  given  on  page  21,  showed 
no  traces  of  lead  or  silver,  but  also  showed  scarcely  a  trace  of  sulphur,  though  the 
rock  at  one  time  certainly  contained  much  iron  pyrites.  Although  it  seems 
strange  that  such  immense  quantities  of  vein-matter  could  be  derived  from  a  sheet 
of  porphyry,  in  this  case  not  more  than  1000  feet  thick  and  on  an  average  not  more 
than  200  or  300  feet  thick,  it  is  hard  to  account  for  the  formation  of  the  currents 
in  any  other  way.  There  is  absolutely  no  proof,  as  far  as  could  be  ascertained, 
that  the  vein-matter  came  from  below  ;  and  though  development  has  been  exten- 
sive throughout  the  camp,  none  of  the  alleged  "  feeders"  have  been  struck. 

The  only  theory  regarding  the  formation  of  the  deposits  that  is  founded  on  a 
careful,  thorough  and  protracted  study  of  the  deposits  of  the  whole  camp  is  that 
given  by  Emmons  in  his  abstract  of  his  main  Government  Report.  It  is  only 
through  such  a  protracted  examination  of  the  deposits,  involving  not  only  a 
careful  inspection  of  all  the  mines  but  a  great  number  of  delicate  chemical  analyses, 
that  any  trustworthy  conclusions  can  be  reached.  The  data  from  which  his 
theory  is  deduced  are  not  yet  published,  but  his  published  conclusions  account 
most  satisfactorily  for  all  the  phenomena  of  the  deposits  developed  in  the  Morning 
and  Evening  Star  mines. 


PART   SECOND. 


METHODS   OF   EXTRACTING  THE   ORES. 


THE  SHAFTS. 

There  are  two  general  methods  of  taking  ore  out  of  the  mines  in  use  at 
Leadville;  one  by  means  of  an  incline  starting  from  the  surface  and  running 
into  the  hill  along  the  mineral  zone,  the  other  by  means  of  a  shaft  sunk  perpendic- 
ularly until  the  ore  is  struck.  The  latter  method  is  used  on  the  Morning  and 
Evening  Star  properties,  though  often  in  combination  with  the  former;  that  is, 
with  an  incline  following  the  ore  from  the  bottom  of  a  shaft  along  the  contact, 
through  which  the  ore  and  waste  are  conveyed  to  the  shaft  by  the  hoisting-engine. 

It  has  been  stated  in  a  preceding  chapter  that  the  Morning  Star  mine  has  four 
shafts  at  present  supplied  with  engines,  and  that  the  Evening  Star  has  likewise 
four,  of  which  one  is  used  by  the  two  mines  in  common.  The  reason  for  such  a 
number  of  shafts  is  obvious.  The  ore  occurs  in  two  separate  bodies  under  differ- 
ent layers  of  porphyry,  and,  as  far  as  present  developments  show,  widely  removed 
from  each  other  horizontally.  Hence  the  ore  of  each  mine  could  only  be  taken 
out  through  one  large  shaft  by  running  long  and  expensive  drifts  and  by  handling 
the  ore  a  great  number  of  times.  It  is  also  more  convenient  tb  have  several  shafts 
on  each  body  of  ore,  because  the  very  slight  dip  of  the  porphyry  soon  carries  the 
workings  a  long  way  horizontally  from  the  shaft,  giving  rise  to  the  same  difficul- 
ties mentioned  above.  On  the  other  hand,  the  distance  of  the  ore  below  the  sur- 
face is  so  short,  varying  from  80  to  400  feet,  that  the  cost  of  sinking  is  not  very 
great,  while  a  number  of  shafts  allows  less  work  for  each,  and  they  can  be  small 
and  supplied  with  light  machinery. 

On  the  Morning  Star  all  the  shafts,  with  one  exception,  were  sunk  to  contact 
before  the  consolidation,  and  that  one  was  nearly  completed,  so  that  the  present 
company  has  not,  until  lately,  found  another  necessary.  On  the  Evening  Star  the 
main  shaft  was  already  sunk  to  contact  when  the  property  was  bought  in  1879. 
The  upper  shaft  was  sunk  later  by  the  present  company,  and  the  Raworth  shaft 
by  the  side  of  the  main  shaft  when  the  latter  proved  inadequate  for  raising  the  ore 
of  the  main  ore-body. 

All  these  shafts  are  small.  They  are  rectangular  in  shape  and  have  two  com- 
partments, one  for  a  ladder-way,  the  other  for  hoisting.  In  the  Lower  Waterloo 
the  ladder-way  has  been  converted  into  a  pumping-compartment.  In  the  new 
McHarg  shaft  of  the  Morning  Star  there  will  be  a  large  pumping-compartment, 


EXTRACTING   THE  ORES. 


but  no  ladder-way, 
shafts : 


The  following  tables  will  show  the  dimensions  of  the  various 


SHAFTS  ON  THE  MORNING  STAR. 


NAME  OF  SHAFT. 

No. 

Depth  to  Con- 
tact. 

Dimensions  of  Lad- 
der-way. 

Dimensions  of  Hoist- 
ing-Compartment. 

Size  of  Shaft  in  the 
clear. 

I 

460 

4x5 

*,  X  5 

c  x  O   2 

Main  Shaft  

2 

265 

3.8  x  4 

4x4 

4X8 

Old  Waterloo  

5 

135 

3.4  x  3.5 

3-5  x  3-5 

3.c  x  7 

6 

140 

3-3  x  3-3 

3.3  x  3.3 

3.3x7 

McHarg  Shaft  

4.5x5 

4x5 

5  X  O 

SHAFTS  ON  THE  EVENING  STAR. 


NAME  OP  SHAFT. 

No. 

Depth  to  Con- 
tact. 

Dimensions  of  Lad- 
der-way. 

Dimensions  of  Hoist- 
ing-Compartment. 

Size  of  Shaft  in  the 
clear. 

Main  Shaft  

10 

116 

3-7  x  4 

4x4 

4x8 

Upper  Shaft  

II 

4OO 

3.2  x  3.2 

4.2X4.4 

a   2  X  7 

3.7  x  4 

4x4 

4x8 

7 

81 

3.2  x  3.3 

•3.2  X  4.6 

32X7 

COST  OF  SINKING  THE  SHAFTS. — There  were  no  records  kept  of  the  cost  of 
sinking  the  old  shafts.  The  new  McHarg  shaft  has  reached  a  depth  of  300  feet 
(May  i,  1883),  of  which  White  porphyry  occupied  the  first  18*0  feet,  and  iron  and 
limestone  the  remaining  distance.  The  cost  of  sinking  this  300  feet,  including 
putting  the  timbers  in  place,  was  not  quite  $18  per  foot.  The  cost  of  the  timber 
and  framing  brings  the  total  cost  of  the  shaft  completed  to  $23.50  per  foot. 

METHODS  OF  TIMBERING  THE  SHAFTS. — The  soft  nature  of  the  ground,  and 
its  tendency  to  swell  or  cave,  render  substantial  timbering  necessary ;  and  even 
when  the  larger  timbers  are  used  they  often  bend  in  and  distort  the  lining.  The 
ordinary  methods  of  timbering  shafts,  which  are  in  use  wherever  timber  is  cheap, 
are  adopted  here.  All  the  shafts  are  timbered  with  regular  cribs,  resting  one 
upon  the  other.  The  logs  used  vary  in  size,  but  average  10  to  12  inches  in  diame- 
ter. They  are  usually  sawed  on  the  face  only,  the  other  three  sides  being  left 
round,  but  the  bark  is  always  removed.  The  timbers  of  the  new  McHarg  shaft  of 
the  Morning  Star  are  better  made  than  any  others  on  the  property.  They  are 
shown  in  Fig.  4,  Plate  V.  They  are  sawed  on  all  four  sides,  and  are  9  by  10 
inches  through.  The  lo-inch  face  stands  vertically.  The  tenons  on  the  ends  are 
9  inches  long,  and  the  shoulders  2  inches  each,  so  that  each  set  timbers  one  foot  of 
shaft.  The  shaft  is  to  be  9  feet  by  4  feet  6  inches  in  the  clear,  so  that  the  longer 
timbers  have  the  former  distance  between  the  tenons,  and  the  shorter  the  latter. 

The  timbers  are  put  in  in  the  following  manner :  when  a  convenient  depth 


CLOSING   THE  LEVELS.  51 

has  been  reached  below  the  lowest  timbers — 8  or  10  feet  on  an  average,  but  vary- 
ing according  to  the  nature  of  the  ground — notches  are  cut  into  the  sides  at  each 
end,  and  cross-pieces,  prolonged  beyond  the  tenon,  as  in  b,  Fig.  4,  Plate  V,  are 
fitted  into  them  horizontally.  Then  the  sets  are  built  upon  these  until  those 
above  are  reached.  Every  other  set  is  wedged  in  place  firmly  by  blocks  or 
wedges  driven  back  of  it,  and  any  large  spaces  behind  are  filled  with  blocks. 
Fig.  i,  Plate  VI,  represents  a  section  of  shaft  showing  the  way  the  long  cross- 
piece  is  put  in.  The  shaft  is  divided  into  two  compartments  by  heavy  planking 
put  across  and  held  in  place  by  3-  or  4-inch  scantling,  which  is  spiked  to  the  tim- 
bers. Four-inch  planking  at  least  should  be  used  for  this  purpose,  as  anything 
thinner  is  apt  to  be  bent  in  and  broken,  needs  constant  repairing,  and  may  cause 
accidents  by  catching  the  bucket  as  it  ascends.  The  new  shaft  is  to  have  6-inch 
division  planking. 

When  a  shaft  reaches  the  contact  a  drift  is  always  run  from  that  point.  If 
there  is  but  this  one  level  the  timbers  are  supported  on  four  heavy  posts,  although 
the  method  of  timbering  and  the  pressure  of  the  ground  against  the  cribs  pre- 
vent very  much  weight  from  settling  upon  them.  Each  pair  of  these  posts  rises 
from  a  sill  and  is  surmounted  by  a  cap.  They  are  similar  to  the  square  sets  to  be 
described  later  on.  If  there  is  a  sump  it  is  timbered  like  the  shaft,  these  cribs 
starting  below  the  sets  at  the  bottom  of  the  drift.  When  the  level  is  above  the 
bottom  the  arrangement  may  be  the  same,  except  that  the  posts  then  set  a  little 
further  out  so  that  they  may  rest  upon  firm  ground.  Sometimes  the  cribbing 
does  not  stop,  but  runs  all  the  way  down.  A  place  is  then  cut  in  the  side  and  a 
frame  put  in  for  the  landing  at  the  first  level.  The  height  of  these  sets  varies ; 
where  there  is  no  incline  they  are  generally  6  feet  high. 

CLOSING  THE  LEVELS. — When  an  upper  level  is  not  in  use  it  is  closed  by  a 
door.  The  door  most  commonly  used,  and  by  far  the  simplest  and  most  conven- 
ient, is  arranged  as  follows :  two  strong  hinges  hold  it  to  the  edge  of  the  sill  of 
the  set  at  the  shaft,  and,  as  the  length  of  the  door  is  made  greater  than  the  height 
of  the  set,  the  top  rests  against  the  side  of  the  cap  towards  the  shaft  when  the 
level  is  closed,  and  is  held  there  by  a  counterpoise.  When  the  level  is  in  use  the 
door  is  thrown  back  against  the  opposite  side  of  the  compartment,  and  its  weight 
is  then  sufficient  to  keep  it  there.  The  bottom  formed  by  such  a  door  has  a 
slope  of  about  60°,  and  the  bucket,  on  striking  it,  slides  into  the  drift.  The  face  of 
the  door  has  longitudinal  strips  of  boiler-plate  riveted  on  it  to  keep  the  bucket 
from  tearing  the  wood.  Where  an  incline  is  used  and  a  truck  has  to  be  run 
under  the  shaft,  as  at  the  first  level  of  the  Morning  Star  main  shaft,  the  door  is 
made  shorter,  so  that  it  just  reaches  across  the  shaft  and  rests  horizontally  on  a 
support  fastened  to  the  other  side.  The  truck  then  runs  up  on  a  track  which 
is  spiked  on  the  back  of  this  door. 


EXTRACTING    THE  ORES. 


THE    DRIFTS. 

Drifting  commences  from  the  contact.  The  drifts  are  either  horizontal,  i.e 
drifts  which  run  along  the  strike,  or  inclines  which  follow  the  dip  of  the  por- 
phyry. A  level  drift  does  not  change  its  height  on  running  into  a  shaft.  The  set 
in  the  shaft  is  the  same  height  as  the  rest.  When  there  is  an  incline  with  a  track 
the  first  few  sets  from  the  shaft  are  higher,  and  gradually  run  down  to  the  normal 
height  of  the  drift,  so  that  a  more  gradual  turn  for^the  rope  may  be  obtained. 
Owing  to  the  loose  nature  of  the  ground  and  its  great  tendency  to  cave,  the  drift 
timbers  have  to  be  very  substantial,  and,  although  they  are  obtained  at  reasonable 
prices,  they  form,  after  the  labor  and  smelting  accounts,  the  largest  item  of  ex- 
pense. The  lumber  and  timber  used  is  all  pine,  the  only  tree  that  grows  in  great 
abundance  about  Leadville. 

COST  OF  TIMBER. — The  timber  is  bought  as  round  logs,  and  contracts  are 
made  for  its  delivery  at  the  mines.  The  following  were  the  prices  paid  by  the 
Evening  Star  mine  for  logs  delivered  during  October  and  November,  1882  : 

Logs  10  feet  long  and  10  inches  in  diameter  at  small  end $o  60 

"     12  "  14  135 

"     14  "  14  "  I  50 

14  "  16  "  I  80 

The  Morning  Star  was  having  delivered  about  the  same  time  the  following 
sizes : .] 

Logs  12  feet  long  and  10  inches  in  diameter  at  small  end $o  75 

"     14  10  080 

"     16  "  10  "  090 

The  annexed  table  of  prices  from  a  contract  of  the  latter  mine  made  in  No- 
vember, 1 88 1,  is  more  complete: 

Logs  14  feet  long  and  12  inches  in  diameter  at  small  end $    40 

14  14  75 

14  16  85 

12  12  .'. 30 

12  14  50 

12  16  60 

16  16  2  10 

12  8  030 

14  6  030 

14  10  090 

14  8  050 

Lagging  16  feet  long  and  4  to  6  inches  in  diameter o  25 

All  the  logs  brought  to  the  mine  for  delivery  must  be  sound  and  good  accord- 
ing to  contract.  They  must  also  be  full  length.  They  are  carefully  inspected 


THE  CAPS.  53 

before  unloading,  and  any  logs  crooked,  unsound,  short,  or  in  any  way  failing  to 
comply  with  the  terms  of  contract  are  rejected.  A  certain  time  is  set  during 
which  the  logs  are  to  be  delivered,  and  generally  a  given  number  has  to  be 
brought  each  week.  Weekly  payments  of  75  per  cent  are  made  for  logs  deliv- 
ered and  the  balance  is  paid  when  the  contract  is  fulfilled.  All  the  mining, 
timbers  are  made  from  these  logs. 

TIMBERING  DRIFTS. 

In  timbering  drifts  the  ordinary  set  is  used,  consisting  of  a  sill,  posts,  cap  and 
braces.  Besides  these,  wedges  are  used  to  hold  them  in  place,  and  lagging  to  hold 
up  the  loose  dirt.  A  brief  description  of  these  pieces  may  be  advisable,  as  they 
have  to  be  carefully  made. 

THE  POSTS. — These  are  made  of  various  sizes.  Heavy  or  light  ones  are  used 
according  to  the  nature  of  the  ground  and  the  amount  of  use  the  drift  will  be 
put  to,  but  the  same  sized  timbers  are  used  throughout.  Generally  the  logs  are 
sawed  on  the  face  only,  and  are  left  round  on  the  other  three  sides.  A  tenon  of 
2  inches  is  made  at  the  top,  with  shoulders  on  the  front  and  the  two  sides.  The 
front  shoulder  is  always  2  inches  deep;,  the  side  shoulders  only  about  i,  but 
vary  according  to  the  size  of  the  log,  as  the  tenon  has  the  fixed  width  and  the 
space  left  over  on  either  side  forms  the  lateral  shoulders.  Thus  if  a  1 2-inch  post 
were  to  be  made  from  a  14^-inch  log,  the  tenon  would  be  just  12  inches  across  and 
ij  inches  would  be  left  for  each  side  shoulHer.  The  faces  of  the  tenon  are  care- 
fully squared,  and  the  top  made  square,  with  the  front  face  of  the  post.  The 
bottom  of  the  post  has  no  tenon,  but  is  sawed  off  square.  The  length  varies 
according  to  the  use  to  which  the  drift  is  to  be  put.  For  an  ordinary  track-drift 
the  posts  are  6  feet  4^  inches  long  over  all.  A  post  is  shown,  drawn  to  scale,  in  b, 
Fig.  i,  Plate  V.  It  is  made  from  squared  timber,  as  is  sometimes  done,  but  does 
not  differ  from  the  round  posts  in  any  other  way. 

THE  SILLS. — These  are  not,  as  a  rule,  as  heavy  as  the  posts ;  they  are  often 
sawed  square,  and  always  on  the  upper  and  lower  sides.  They  are  usually  8 
inches  thick  and  12  inches  wide  when  made  for  a  1 2-inch  post.  They  have  a 
9-inch  tenon  at  each  end,  with  one  shoulder  of  2^  inches  on  the  upper  side.  The 
posts  rest  upon  these  tenons,  and  the  faces  come  close  against  the  shoulders. 
The  length  between  the  tenons  is  generally  4  feet.  Fig.  2,  Plate  V,  shows  a  sill. 

THE  CAPS. — The  caps  are  made  of  logs  corresponding  to  the  posts  in  size. 
When  the  latter  are  not  square,  neither  are  the  caps,  but  are  then  sawed  only  on 
the  lower  side.  They  have  a  tenon  at  each  end  which  is  9  inches  long  on  the 
under  side.  On  this  side  the  collar  is  2  inches  deep.  When  this  tenon  rests  on 
the  top  of  the  post,  the  shoulder  of  the  cap  comes  against  the  tenon  of  the  post 


54  EXTRACTING   THE  ORES. 

and  the  face  of  the  cap  rests  against  the  front  shoulder  of  the  post.  There  are 
shoulders  on  the  sides  of  the  cap  also,  but  these  are,  like  those  on  the  post, 
seldom  over  i  inch  deep.  They  start  2  inches  back  of  the  lower  shoulder ;  that 
is,  1 1  inches  from  the  end  of  the  cap.  The  length  of  the  cap,  like  that  of  the 
sill,  varies  greatly.  Usually  it  is  5  feet  10  inches  over  all ;  that  is,  4  feet  in  the 
clear,  a,  Fig.  i,  Plate  V,  represents  a  cap.  It  is  turned  lower  side  up  to  give  a 
better  view  of  the  tenon. 

COLLAR-  AND  FOOT-BRACES. — These  are  made  of  sawed  timber.  They  are  8 
by  10  inches  thick,  and  of  varying  length.  They  are  sent  down  the  mine  in  long 
pieces  and  cut  of  the  length  required  when  the  set  is  put  together.  The  collar- 
brace  rests  on  the  lateral  shoulders  of  the  posts  and  against  those  of  the  caps. 
The  foot-braces  lie  on  the  floor  of  the  drift  between  the  posts. 

Fig.  3,  Plate  V,  shows  three  sets  of  drift  timbers  of  about  the  usual  strength 
for  an  ordinary  track-drift.  From  this  figure  it  may  be  seen  how  the  various 
timbers  fit  upon  one  another.  It  must  be  remembered  that  in  the  ground  the 
space  between  the  sills  is  filled  in,  and  that  the  foot-braces,  which  do  not  lie  on 
any  shoulders,  rest  upon  this  filling. 

As  accessories  to  the  set  Wedges  and  Lagging  may  be  mentioned. 

WEDGES. — Wedges  hold  the  timbers  in  place  until  pressure  sets  upon  them. 
They  are  made  from  any  suitable  material.  Waste  lumber  or  logs  are  sawed  into 
blocks  1 6  to  1 8  inches  long  and  these  ripped  into  pieces  about  4  inches  square. 
Such  a  piece  is  then  sawed  from  one  end  edge  diagonally  across  to  the  other, 
thus  forming  two  wedges. 

LAGGING. — This  is  only  used  where  the  ground  is  loose  enough  to  cave.  It  is 
generally  required  over  the  caps  and  often  behind  the  posts.  It  may  be  of  any 
light  material,  but  is  most  commonly  round  sticks  3  to  5  inches  in  diameter. 
These  are  of  any  convenient  length,  frequently  about  that  of  two  sets.  The  ends 
of  the  pieces  are  cut  obliquely  on  opposite  faces  so  that  they  form  parallel  sur- 
faces. They  then  fit  end  to  end  and  make  a  tight  joint.  Any  other  light  material, 
like  slabs,  may  be  used  for  lagging.  Everything  used  in  drift-timbering  has  now 
been  mentioned. 

Certain  precautions  should  be  used  in  making  these  timbers  and  putting  them 
together.  The  following  are  the  most  important:  (i)  In  making  the  various 
timbers,  care  should  be  taken  that  they  fit  perfectly  when  put  together.  The 
tenons  and  shoulders  should  be  made  accurately  to  measurements  and  carefully 
squared.  The  centre-lines  should  be  plainly  marked  on  the  inside  faces  so  that 
they  may  be  used  in  putting  up  the  set.  (2)  In  ordinary  drifts  the  sets  should 
stand  perfectly  vertical.  The  sill  should  be  placed  with  the  utmost  care,  as  the 
strength  and  durability  of  the  set  depend  greatly  upon  this.  A  trench  is  dug  for 
it,  and  the  sill  then  set  in  with  the  upper  face  perfectly  horizontal,  and,  in  a  level 


COST  OF  DRIFT-TIMBERS. 


55 


drift,  on  a  level  with  the  preceding  sill.  If  the  drift  has  a  slight  inclination,  say  of 
2  inches  per  set,  the  sill  is  given  this  difference  of  level.  In  preparing  this  trench, 
especially  where  the  ground  is  not  very  hard,  the  center  should  be  dug  lower 
than  the  ends,  so  that  the  middle  of  the  sill  cannot  touch.  The  pressure  of  the 
roof,  exerted  through  the  posts,  presses  the  ends  of  the  sill  into  the  ground,  and, 
when  the  ends  sink,  if  the  middle  meets  with  resistance  it  will  spring  up  and  the 
sill  will  be  broken,  just  as  a  stick  is  broken  across  the  knee.  Neglect  of  this  pre- 
caution constantly  results  in  the  breaking  of  sills,  this  being  one  of  the  most  com- 
mon ways  in  which  they  are  destroyed.  The  necessity  for  removing  the  ground 
that  would  bear  at  the  center  applies  also  in  placing  the  posts  and  caps.  Fig.  2, 
Plate  VI,  shows  typically  how  the  ground  should  bear  on  a  set  in  a  drift.  (3) 
The  lagging  should  be  neither  too  strong  nor  too  close  together.  Soft  ground 
will  often  swell  for  a  time  after  it  is  exposed  with  irresistible  force.  If  the  lag- 
ging be  too  close  this  will  easily  break  it,  while  if  it  be  further  apart  the  soft 
ground  will  be  forced  into  the  interstices  and  the  pressure  will  thus  be  relieved. 
It  is  for  this  reason,  also,  that  round  logs  are  often  preferred  to  square  ones  in 
timbering  winzes  which  pass  through  vein  matter.  Where  the  ground  is  not  soft 
and  plastic,  but  dry  and  very  crumbly,  close  lagging  may  be  advisable.  The 
harm  resulting  from  using  too  strong  lagging  is  also  apparent.  As  long  as  the 
pressure  is  not  excessive  the  lagging  should  hold  up  the  ground.  But,  since  all 
the  pressure  on  it  is  conveyed  to  the  sets,  if  the  lagging  be  very  strong  this  may 
be  sufficient  to  crush  them.  It  is,  however,  better  for  the  lagging  to  bend  or 
break,  as  it  costs  much  less  than  the  sets. 

COST  OF  SETS. — The  cost  of  the  various  pieces  of  a  set,  framed  and  ready 
to  be  put  up  is  given  below.  The  posts  are  ordinary  ones  of  1 2-inch  tenon ;  that 
is,  made  from  a  14-inch  log.  Sets  three  feet  apart  from  centre  to  centre. 


Timber. 

Framing. 

Sawing. 

Total. 

One  sill  

$0  67 

$0  18 

$O  IO 

$°  95 

I  50 

22 

IO 

i  82 

68 

4O 

05 

I  13 

Two  collar-  bracec  

ao 

30 

3O 

30 

Total  ,  

$3  45 

$0    80 

$o  25 

$4  50 

The  distance  of  the  sets  apart  varies  according  to  the  nature  of  the  ground. 
Sometimes  they  are  not  more  than  2\  feet  from  centre  to  centre,  sometimes  they 
are  as  much  as  5  feet.  The  average  is  about  3  feet,  which  would  make  the  cost  of 
the  framed  timbers  $1.50  per  running  foot  of  drift.  This  estimate  is  exclusive  of 
wedges,  lagging,  and  the  cost  of  putting  the  sets  in  place,  which  would  bring  the 
cost  very  nearly  up  to  $2  per  foot. 


56  EXTRACTING   THE  ORES. 


THE   STOPES. 

* 

The  pressure  on  the  sets  is  often  enormous.  It  may  arise  from  two  causes, 
swelling  of  the  ground,  owing  to  access  of  air,  or  an  actual  caving  or  settling  of 
the  roof.  The  latter  is  far  the  more  powerful  source  of  pressure,  and  is  more 
common  than  the  other,  especially  under  the  White  porphyry.  When  a  large 
body  of  ore  is  being  stoped  along  a  drift  the  whole  region  settles.  The  caps  are 
often  crushed  to  splinters  on  the  posts  and  broken  in  the  middle,  while  the  sills 
spring  up  at  the  center  and  thus  almost  close  the  drift.  To  support  the  roof  in  the 
slopes  the  most  substantial  methods  of  timbering  have  to  be  employed.  The  stope 
supports  are  simple.  They  are  stulls  and  head-blocks,  cribbing  and  square  sets. 

STULLS  AND  HEAD-BLOCKS. — These  are  employed  as  temporary  supports  to 
hold  the  roof  during  sloping  until  more  permanent  ones  can  be  made.  They  may 
be  permanenl  only  where  Ihe  stope  is  very  small  and  the  spaces  between  them 
are  at  least  partially  filled  with  waste.  The  stull  is  merely  a  post  or  log,  and  is 
made  10  or  12  inches  shorter  than  Ihe  dislance  belween  Ihe  walls  where  il  is  to 
be  used.  The  head-block  is  a  block  sawed  on  two  opposite  faces,  and  about  i  foot 
thick  by  16  inches  broad  and  2  feet  long.  In  selling  Ihem  up  a  smooth  place  is 
made  on  Ihe  floor  for  Ihe  slull,  and  on  Ihe  roof  for  Ihe  block.  The  stull  is  then 
put  up  and  the  block  put  over  it.  Wedges  are  driven  above  the  block  until  Ihe 
stull  is  held  in  position.  Pressure  soon  setlles  upon  it,  and  it  is  then  held  lighlly. 
The  slull  is  always  pul  in  al  right  angles  to  the  roof.  Fig  4,  Plale  VI,  shows  a 
slull  in  posilion.  The  wedge  used  lo  hold  it  up  in  Ihe  firsl  place  is  driven  from 
Ihe  lower  side. 

CRIBBING. — Cribs  are  Ihe  mosl  common  slope  supports  in  the  Evening  and 
Morning  Star  mines,  and,  though  Ihe  mosl  expensive,  are  by  far  Ihe  mosl  sub- 
slanlial  and  safe  supports.  Where  Ihe  ore-body  is  very  large  Ihey  are  almosl 
indispensable.  Cribs  are  generally  reclangular  in  shape.  When  large,  each  crib 
or  set  consisls  of  five  logs,  Iwo  large  ones,  notched  at  the  middle  and  each  end  on 
both  sides,  and  three  shorter  ones,  notched  only  at  Ihe  ends.  Two  long  logs  are 
laid  down,  and  Ihree  short  ones  are  placed  across  Ihem,  Ihe  nolches  filling  inlo 
each  olher ;  Ihen  Iwo  more  long  ones,  and  so  on  up,  sel  above  sel,  unlil  Ihe  roof 
is  reached.  If  Ihe  plalform  on  which  Ihey  resl  be  nol  horizontal,  an  extra  log  is 
put  under  the  lower  side  as  in  the  figure.  The  size  of  the  logs  varies,  but  com- 
monly a  lo-lo  12-inch  log  is  employed. 

The  cribs  are  carried  lo  Ihe  roof,  and  Ihe  compartmenls  in  them  are  carefully 
filled  as  full  as  possible  with  waste,  as  Ihis  helps  lo  keep  Ihe  cribs  in  shape  and  to 
support  the  pressure.  Il  is  also  well,  if  Ihe  cribs  are  very  high,  to  fill  the  spaces 
between  the  logs  with  small  timber,  as  Ihis  will  receive  a  part  of  Ihe  pressure  when 


SQUARE  SETS.  57 

the  cribs  settle  and  remove  that  much  from  the  ends  of  the  logs.  Some  of  the 
cribs  of  the  Evening  Star  are  between  70  and  80  feet  high,  and  they  are  found  to 
be  the  only  thing  that  will  support  the  roof  in  such  places.  Fig.  3,  Plate  VI, 
shows  the  form  of  a  set  of  cribs.  The  foundation  and  roof  have  been  smoothed 
off,  and  the  cribbing  is  built  up  vertically  although  the  floor  slants.  The  compart- 
ments are  completely  filled  with  waste. 

SQUARE  SETS.— This  form  of  stope  timber  is  seldom  used  in  either  mine,  es- 
pecially in  the  Morning  Star.  The  square  sets  used  here  differ  from  those  in  use  on 
the  Comstock  Lode  and  described  by  J.  D.  Hague,  and  are  apparently  not  so 
good  a  form.  They  differ  in  no  essential  way  from  the  ordinary  drift  set  already 
described,  only  the  post  has  a  shoulder  on  the  fourth  side  for  an  additional  collar- 
brace.  One  set  is  placed  directly  upon  the  other,  the  cap  of  the  lower  forming  the 
sill  of  the  one  above.  Where  the  ore-body  is  large  and  regular  this  form  of 
support  is  not  now  used.  Where  it  is  very  irregular  and  narrow,  but  runs  some 
distance  vertically,  it  is  always  used.  In  stoping,  if  square  sets  are  to  be  used,  a 
face  is  started  as  wide  as  a  set,  and  extending  from  the  top  to  the  bottom  of  the 
ore,  and  this  is  run  forward  through  the  block  like  a  great  high  drift.  But  if 
cribbing  is  to  be  used  in  a  large  body  they  start  at  the  bottom,  dig  under  the 
body  and  prepare  a  foundation  of  proper  shape  and  size,  and  then  work  up,  stop- 
ing  overhand  and  taking  out  a  pillar.  The  cribbing  is  built  up  as  fast  as  the  ore 
is  taken  down,  and  any  waste  is  utilized  for  filling  up  the  cribs.  In  such  places  it 
is  often  difficult  to  get  waste  for  this  purpose. 

For  making  all  these  timbers  each  mine  is  provided  with  a  saw-mill  and 
framing-rooms.  In  both  cases  they  are  connected  with  a  shaft-house,  and  the 
same  boiler  supplies  the  steam  for  the  hoister  and  the  engine  which  runs  the  saws. 
Only  plain  sawing,  cutting  into  lengths  and  making  wedges  is  done  by  machinery; 
all  the  rest  of  the  framing  is  done  by  hand.  As  soon  as  the  timbers  are  sawed 
they  are  taken  to  the  framing-room,  framed  and  stored  in  piles  of  pieces  of  the 
same  kind  and  size,  ready  for  use.  From  here  they  are  distributed  to  the  various 
shafts  of  the  mine  as  needed.  The  crib  is  either  notched  on  top  with  an  adze  or  is 
sent  below  of  the  desired  length  and  notched  when  used.  The  log-yards  are  just 
above  the  saw-mills,  so  that  the  logs  are  easily  obtained.  A  team  brings  them  to 
the  mill  and  distributes  the  framed  timbers. 

The  cost  of  drift  timbers  has  already  been  given.  Cribs  cost  according  to  the 
size  and  length  of  the  logs  from  which  they  are  made.  Any  pieces  cut  off  the 
regular  length  are  made  into  wedges  or  head-blocks,  and  the  expenses  of  framing 
them  are  small.  The  timber  for  one  crib  of  two  14-foot  logs  and  three  ro-foot 
logs,  all  10  inches  in  diameter  at  the  small  end,  will  cost  $3.60.  Good  lagging 
costs  about  \\  cents  the  running  foot.  Wedges  cost,  ready  made,  a  little  over  i 
cent  apiece,  head-blocks  about  10  cents,  and  stulls  6  cents  the  running  foot. 


58  EXTRACTING   THE  ORES. 


SHAFT-HOUSES. 

Although  the  arrangement  of  several  shaft-houses  on  both  mines  is  more  com- 
pact, that  of  the  Lower  Waterloo  has  other  and  more  important  advantages,  and, 
though  not  so  large,  it  is  in  many  ways  better  than  any  of  the  others.  It  is  more 
complete  and  has  machinery  superior  to  that  of  any  shaft  on  Carbonate  Hill,  and 
the  arrangement  of  the  dumps  is  also  very  good.  It  has  therefore  been  selected 
for  description. 

MACHINERY. — The  hoisting-engine  was  made  by  J.  W.  Jackson,  of  Denver. 
It  is  a  powerful  one  and  capable  of  much  more  work  than  it  is  now  required  to 
do.  The  spool  is  4  feet  in  diameter.  It  is  worked  by  friction  gearing,  as  are 
most  of  the  hoisters  of  the  camp.  The  large  friction-wheel  attached  to  the  spool  is 
6  feet  in  diameter  and  works  against  a  2-foot  paper-tired  wheel.  The  axle  of  the 
wheel  rests  in  eccentric  sockets,  so  that  by  turning  the  latter  one  way  the  large 
friction-wheel  is  thrown  against  the  small,  while  by  turning  the  other  way  it  is 
thrown  against  the  break-block.  The  spool  rests  on  a  solid  wooden  frame  which 
is  on  a  massive  masonry  foundation.  The  rope  is  a  i-inch  steel  wire  cable.  It 
passes  to  the  sheve  over  a  small  pulley  which  revolves  on  a  bar  along  which  it  can 
slide,  keeping  on  a  line  with  the  sheve  and  the  point  where  the  rope  binds  on  the 
spool.  The  sheve  is  4  feet  in  diameter,  and  is  supported  on  a  strong  framework 
over  the  hoisting-compartment,  which  is  carefully  braced  on  the  side  towards  the 
hoister. 

There  is  a  fine  air-compressor  on  the  same  floor.  It  was  made  by  Sargeant  & 
Cullingworth,  of  New  York.  It  was  put  in  for  running  a  pump  at  the  bottom  of 
the  incline  and  for  using  air-drills,  but  so  far  has  been  used  exclusively  for  the 
former  purpose.  This  air-pump  conveys  the  water  to  a  sump  at  the  foot  of  the 
shaft;  from  here  a  steam-pump  of  peculiar  and  not  very  satisfactory  pattern  raises 
the  water  to  the  surface,  a  distance  of  about  200  feet.  The  steam  is  supplied  by 
two  boilers.  At  present  one  of  these  is  able  to  do  all  the  necessary  work,  so  they 
are  run  alternately,  being  changed  every  few  weeks.  The  engineer  attends  to 
the  engine  and  to  firing  the  boilers.  No  firemen  are  employed  at  any  of  the 
shafts. 

The  water  for  the  boilers  is  obtained  directly  from  the  city  mains,  which  run 
immediately  under  the  shaft-house.  A  large  tank  holds  a  reserve,  and  is  filled  at 
will  by  turning  on  the  tap.  The  pressure  in  the  main  is  considerable,  and  all  the 
lower  shafts  get  their  water  in  this  way.  The  upper  shafts,  Nos.  i,  2,  3,  9,  10  and 
n,  Plate  II,  are  too  high  up,  so  each  mine  has  to  have  a  small  steam-pump  which 
supplies  it  with  water  daily.  The  water  is  of  excellent  quality,  containing  little 
or  no  carbonate  of  lime. 


HOISTING-FLOOR.  59 

HOISTING-FLOOR.— The  position  of  this  shaft-house,  like  all  the  others,  is 
with  its  greatest  length  running  up  and  down  the  hill,  in  order  that  the  ore-bins 
may  be  some  distance  above  the  ground,  and  that  a  good  dump  may  be  obtained. 
For  this  reason,  also,  the  hoisting-floor  is  made  higher  than  the  floor  of  the  engine- 
room.  In  this  shaft-house  it  is  only  six  feet  higher.  The  shaft  terminates  at  this 
floor,  and  everything  is  hoisted  to  it.  The  shaft  has  two  compartments ;  one  is 
used  for  pumping,  and  the  other  for  hoisting.  A  bucket,  not  a  cage,  is  used. 
The  hoisting-compartment  rises  8  inches  above  the  floor  all  around.  The  front 
and  back  of  it  have  a  triangular  piece  surmounting  this,  which  is  10  inches  higher 
at  the  middle  than  at  the  sides.  Two  heavy  doors,  hinged  to  the  sides,  rest  upon 
these  pieces.  A  rope  from  each  of  the  doors  passes  over  a  pulley  about  8  feet 
above  it,  and  then  both  ropes  pass  to  one  side  and  join  together ;  this  single  rope 
passes  through  a  third  pulley  and  has  a  counterpoise  attached  to  it.  Hence  when 
one  door  is  pulled  open  or  shut  the  other  is  too,  and  at  the  same  time  they  work 
very  easily.  The  doors  are  always  kept  closed  when  the  bucket  is  down.  Be- 
hind the  shaft  the  floor  is  covered  with  boiler-plate.  From  this  one  track  leads  to 
the  ore-bins  and  waste-dump,  and  another  to  the  "  wash"  dumps,  on  which  any- 
thing hoisted  too  poor  to  pay,  but  rich  enough  to  make  ore  by  dressing,  is 
thrown. 

The  bucket  used  for  hoisting  has  a  capacity  of  6  to  8  cubic  feet.  Some- 
times it  is  of  wood,  especially  where  there  is  no  incline,  but  here  and  at  the 
Morning  Star  main  shaft  it  is  iron.  Iron  buckets  are  made  of  J-inch  boiler-plate, 
with  the  seams  strongly  riveted.  They  are  cylindrical  at  this  shaft,  and  their 
length  and  breadth  are  about  equal.  At  the  other  shaft  they  are  shaped  like  an 
oil  barrel,  and  are  about  the  size  of  one.  The  wooden  buckets  are  of  this  shape, 
made  of  hard  wood  and  bound  with  £-inch  wrought-iron  bands.  When  hoisted, 
the  bucket  strikes  against  the  doors  and  throws  them  open.  It  is  stopped  about  8 
feet  above  the  floor.  The  dumper  then  closes  the  doors  and  fastens  a  hook,  which 
is  suspended  by  a  rope  from  a  point  above  and  behind  the  shaft,  to  a  ring  at  the 
bottom  of  the  bucket.  The  engineer  lowers,  and  the  rope  pulls  the  bucket  back 
and  overturns  it  into  the  car,  which  stands  in  position  against  the  back  of  the 
shaft.  It  is  then  hoisted  to  its  former  position,  the  rope  unhooked,  the  doors 
opened  and  the  bucket  again  lowered  into  the  shaft. 

The  car  used  is  almost  exactly  like  that  described  by  J.  D.  Hague  as  used  on 
the  Comstock  Lode,  the  only  essential  difference  being  in  the  turn-table,  which  at 
Leadville  consists  of  three  plates,  the  upper  two  of  which  are  hinged  together 
and  turn  on  the  third.  The  door  at  the  end  is  the  same  in  both  cases :  hinged  at 
the  top,  and  controlled  by  a  lever  in  front.  These  cars  are  made  at  the  mines,  of 
2-inch  pine  plank.  They  are  lined  with  boiler-plate  and  firmly  braced  on  the 
outside  with  bands  of  the  same  material. 


60  EXTRACTING    THE  ORES. 

ORE-BINS. — The  ore-bins  are  at  some  distance  from  the  shaft,  and  a  covered 
passage  leads  to  them.  This  gives  the  height  above  the  surface  requisite  for  a 
sorting-floor  and  ore-bins  below  it  from  which  the  wagons  are  loaded.  At  this 
shaft  the  bins  are  only  four  in  number,  two  with  grates  and  two  without.  The 
grates  terminate  over  a  sorting-floor  which  is  6  feet  above  the  bins.  Those  with- 
out grates  receive  ore  on  the  lower  floor  immediately,  and  only  such  ore  as  is  not  to 
be  sorted  is  thrown  into  them.  The  gratings  are  4  feet  wide,  and  consist  of  thirty 
£X  ii-inch  wrought-iron  bars  standing  on  edge.  They  have  an  inclination  of  about 
60°,  and  stop  about  \\  feet  above  the  sorting-floor.  Below  them  the  floor  is  guarded 
with  boiler-plate  to  prevent  wear.  When  the  ore  is  thrown  on  these  grates,  all  the 
fine,  which  is  mostly  granular  carbonate  of  lead,  passes  between  the  bars  to  the 
lower  floor,  while  the  lumps  capable  of  being  hand-sorted  fall  on  the  sorting-floor. 
The  sorter  goes  over  all  this,  throwing  the  ore  into  the  bins,  and  the  gangue  on 
the  waste-dump.  The  waste-dump  is  directly  beyond  the  ore-house.  It  receives 
only  such  waste  as  is  very  low  in  silver  and  lead.  Any  waste  running  over  10  or 
12  per  cent  of  lead  is  thrown  on  a  separate  dump  to  await  dressing. 

The  other  large  shaft-houses  are  provided  with  ordinary  Colorado  hoisters 
and  no  other  machinery.  The  Upper  Waterloo  and  Morning  Star  main  shaft- 
houses  are  much  larger  than  the  Lower  Waterloo,  and  the  ore-bins  are  differently 
and  not  so  well  arranged.  These  bins  are  arranged  in  a  row  along  the  hill  so  that 
they  run  across  the  lower  end  of  the  shaft-house,  forming  a  sort  of  letter  T. 
The  car  containing  ore  is  run  to  the  crest  of  the  bins  and  then  turned  on  a  piece 
of  boiler-plate  to  a  track  at  right  angles  running  along  the  edge  of  the  bins. 
These  bins  are  ten  in  number,  five  with  gratings  and  five  without.  The  car  not 
only  has  to  be  turned  twice  every  time  the  ore  is  brought  up,  but,  unless  the  hill 
is  very  steep,  the  hoisting-floor  has  to  be  raised  very  high  above  the  ground  to 
afford  sufficient  dump.  The  Morning  Star  shaft  has  its  floor  about  20  feet  above 
the  ground. 

All  the  shaft-houses  have  sorting-floors,  and  ore-sorters  are  constantly  em- 
ployed in  taking  out  the  gangue.  Sorting  not  only  lessens  the  amount  of  ore 
smelted,  but  as  the  percentage  of  lead  is  increased  the  price  paid  per  ton  for 
smelting  is  lessened,  and  the  price  received  for  the  lead  is  greater  per  pound.  An 
example  will  show  this  more  plainly.  Suppose  56  tons  of  ore  mixed  with  waste 
averages  before  sorting  29  per  cent  lead  and  35  ounces  silver.  If  sent  to  the 
smelter  it  would  sell  as  follows : 

Received  for  lead,  at  :J  cents  per  pound  $406  oo 

"         "    silver,  at  $1.07  per  ounce 2097  20 

$2503  20 
Paid  for  smelting,  at  $14  per  ton 784  oo 

Received  from  smelter $1719  20 


JDXIFTS.  6 1 

If  the  ore  had  been  sorted  and  brought  down  to  50  tons,  assaying  32  per  cent 
lead  and  38  ounces  silver : 

Received  for  lead,  at  i£  cents  per  pound $480  oo 

'    silver,  at  $1.07  per  ounce 2033  oo 

$2513  oo 
Paid  for  smelting,  at  $13  per  ton , 650  oo 

Received  from  smelter $1863  oo 

The  practice  of  putting  all  the  waste  raised  that  is  capable  of  making  ore  by 
dressing  on  separate  dumps  is  now  in  use  at  all  the  shaft-houses  on  the  Morning 
and  Evening  Star,  and  both  mines  now  have  large  quantities  of  this  material  on 
hand.  The  third-class  dump  of  the  Upper  Waterloo  gave,  by  assay  from  a  num- 
ber of  samples  carefully  taken,  from  27  to  30  per  cent  of  lead  and  from  4  to  6 
ounces  of  silver  per  ton.  This  dump  is  higher  in  lead  and  lower  in  silver  than 
any  of  the  others. 

Bancroft  UbrS$ 

UNDERGROUND   WORKINGS. 


DRIFTS. — All  the  shafts  worked  either  strike  the  ore  or  come  very  near  it. 
As  soon  as  contact  is  reached  development  is  begun  by  running  exploring  drifts 
along  the  contact.  They  are  either  horizontal  or  have  a  decided  dip.  Such  drifts 
may  be  divided  into  two  classes;  (i)  regular  highways  which  collect  all  the 
material  to  be  hoisted  and  convey  it  towards  the  shaft,  and  (2)  numerous  branches 
of  these  which  run  off  developing  the  ground,  each  serving  at  most  as  the  out- 
let for  only  a  limited  territory.  The  former  are  the  larger,  more  carefully  made 
and  better  timbered.  They  are  always  supplied  with  a  tramway  along  which  the 
ore  and  waste  is  conveyed  in  cars  or  in  buckets  set  upon  trucks.  The  latter, 
being  comparatively  little  used,  are  less  strongly  timbered,  and  where  the  ground 
is  good,  as  in  the  Lower  Waterloo,  sometimes  not  at  all.  They  have  no  tramway 
and  are  not  necessarily  smooth  like  the  former.  The  vein-matter  taken  out 
through  them  is  conveyed  to  the  nearest  track-drift  in  wheelbarrows.  If  a  shaft 
or  level  has  no  incline  up  which  the  ore  is  drawn  by  the  hoister,  only  the  ore  on 
or  above  that  level  is  taken  out  by  it,  as  the  dip  is  too  steep  to  move  the  ore  up 
hill  by  hand.  If  there  is  such  an  incline  the  ore  may  be  taken  out  for  an  indefinite 
distance  below.  The  Morning  Star  main  shaft,  No.  2,  Plate  III,  and  the  Lower 
Waterloo  shaft,  No.  6,  Plate  III,  are  the  only  ones  that  have  such  inclines.  In 
both  cases  the  incline  serves  as  a  main  outlet,  and  side-drifts  run  out  from  it  hori- 
zontally. Cross-drifts  are  again  run  from  these,  dividing  the  ground  up  into 
blocks  and  fully  exploring  it.  The  Morning  Star  incline  is  the  better  of  the  two. 
It  begins  at  the  point  where  the  shaft  strikes  the  contact  and,  following  the  con- 


62  EXTRACTING    THE  ORES. 

tact,  runs  to  the  end  of  the  property.  It  is  not  shown  on  the  section.  This 
incline  is  perfectly  straight  and  substantially  timbered  with  1 2-inch  sets  (i4-inch 
logs).  A  single  track  runs  down  it.  The  first  15  feet  from  the  shaft  is  horizontal, 
though  the  sets  are  higher,  so  that  the  top  keeps  the  regular  slope  of  the  incline. 
The  set  in  the  shaft  has  a  lo-inch  drum  at  the  top.  When  a  bucket  is  to  be  sent 
from  the  surface  down  the  incline  it  is  lowered  to  the  level.  The  trammer  has  a 
low  truck  at  the  foot  of  the  shaft  to  receive  it.  A  chain  just  of  the  right  length  is 
fastened  to  the  front  of  the  truck.  The  trammer  receives  the  bucket,  guides  it  to 
its  proper  position  on  the  truck,  sees  that  it  rests  with  its  ears  across  the  drift, 
and  hooks  the  chain  over  the  rim.  He  then  pulls  the  truck  over  the  crest  of  the 
incline  and  jumps  on.  The  engineer,  having  merely  paused  at  the  level  long 
enough  for  the  bucket  to  be  properly  adjusted,  now  lowers  it  to  its  destination. 
On  hoisting,  the  trammer  comes  upon  the  truck  and  loosens  the  chain  just  after 
the  crest  is  reached,  thus  leaving  the  bucket  free  to  go  up  without  stopping.  The 
rope  used  is  hemp,  which  is  much  better  for  this  purpose  than  wire.  It  bends 
over  the  drum  in  the  set  at  the  foot  of  the  shaft,  and  over  rollers  at  any  point 
along  the  incline  where  the  slope  changes.  At  various  points  on  either  side  of 
this  incline  horizontal  drifts  have  been  run,  and  from  these  smaller  drifts.  All  the 
ore  is  brought  to  the  incline  through  these,  and  there  transferred  to  the  bucket. 
Some  of  these  drifts  on  the  south  side  are  outlets  of  quite  extensive  workings,  and 
are  provided  with  tramways  and  cars. 

The  arrangement  at  the  Lower  Waterloo  is  much  less  convenient,  and  develop- 
ing work  only  is  pushed  on  down  this  incline.  It  is  intended  to  take  out  the  ore 
through  the  new  McHarg  shaft,  which  will  strike  this  contact  below  the  present 
workings.  A  level  drift  runs  from  the  second  level  of  the  shaft  out  200  feet  to 
the  south-east  till  contact  is  reached,  and  here  a  very  steep  incline  begins,  so  steep 
that  it  is  not  safe  for  a  man  to  ride  down  it.  A  special  truck  and  bucket  have 
been  devised  for  use  on  this  incline,  the  rope  being  fastened  to  the  truck. 

The  Evening  Star  upper  shaft  has  also  an  incline,  but  with  a  very  moderate 
slope,  and  the  ore  about  it  was  hauled  to  the  shaft  by  a  donkey  kept  underground 
for  this  purpose.  All  the  other  shafts  and  levels  work  only  the  ground  at  or 
above  their  own  level,  and  long  horizontal  drifts  run  from  these  to  collect  the  ores 
from  the  contact. 

CHUTES. — In  a  stope  the  ore  is  thrown  or  wheeled  to  the  nearest  track-drift 
below  to  be  taken  out.  Instead  of  throwing  it  on  the  floor  of  the  drift,  where  it 
would  be  greatly  in  the  way  and  from  whence  it  would  have  to  be  shovelled  into 
the  cars,  the  ordinary  chute  is  used  when  possible.  These  extend  either  from 
some  accessible  point  in  the  stope  to  the  track-drift  below  or,  more  commonly, 
from  a  drift  which  in  turn  leads  to  the  stope.  Chutes  are  from  3  to  6  feet  wide  at 
the  top  and  \\  feet  at  the  bottom,  and  are  about  i  foot  deep.  They  run  from  the 


STOPING   THE  ORE.  63 

bottom  of  the  upper  drift  to  the  side  of  the  lower,  and  protrude  enough  for  the 
car  or  bucket  to  be  pushed  under  them.  A  sliding  door  at  the  bottom  closes 
them  so  that  the  contents  will  not  fall  out.  If  two  drifts  cross  one  above  the  other 
a  chute  may  be  run  from  the  bottom  of  one  to  the  top  of  the  other  at  the  point  of 
crossing.  The  Upper  Waterloo  has  an  excellent  double  chute  of  this  kind.  It 
runs  from  a  track-drift  which  is  the  outlet  of  a  great  deal  of  pure  carbonate  of 
lead  to  the  main  double-track  drift  running  from  the  second  level  of  the  shaft. 
At  the  place  where  they  cross  a  broad  chute  is  run  from  each  side  of  the  upper 
drift  into  the  top  of  the  lower.  As  the  drifts  are  close  together  the  chutes  are 
short,  but  being  very  broad  they  hold  a  great  deal.  At  the  end  of  each  chute 
there  are  two  doors,  one  over  each  track.  One  chute  is  used  exclusively  to  re- 
ceive ore,  the  other  waste.  It  is  often  desirable  to  have  a  double  chute  where  the 
drifts  do  not  cross,  so  that  ore  and  waste  may  be  sent  down  and  yet  never  go  into 
the  same  receptacle.  For  this  end  a  very  broad  chute  is  made  with  two  doors  at 
the  lower  end,  and  a  middle  partition  which  runs  nearly  to  the  top.  On  this  par- 
tition a  door  is  hinged  which  swings  from  one  side  to  the  other.  Thus  when  one 
side  is  in  use  the  other  side  is  closed.  If  the  chute  starts  from  the  bottom  of  a 
drift  instead  of  the  side,  the  door  is  hinged  to  the  bottom  along  the  middle  line  of 
the  chute. 

WINZES. — In  the  Evening  Star  the  ore-bodies  were  so  thick  that  the  main 
drift  for  conveying  the  ore  to  the  shaft  would  be  20  and  even  60  to  80  feet  below 
the  contact.  In  such  cases  winzes  are  sunk  from  the  upper  workings  to  the 
lower,  down  which  the  ore  is  thrown.  To  avoid  accidents  winzes  are  generally 
made  at  the  ends  or  sides  of  drifts.  They  are  timbered  with  cribs  just  like  shafts, 
only  the  logs  are  lighter.  They  are  tightly  lined  with  planking  running  up  and 
down  to  prevent  the  rocks  from  destroying  the  timbers. 

STOPING  THE  ORE. — When  new  ground  has  been  thoroughly  developed  the 
ore,  if  in  considerable  quantity,  is  left  standing  in  reserve  until  the  management  is 
ready  to  take  it  out.  In  the  mean  time  everything  is  prepared  so  that  it  may  be 
removed  in  the  cheapest  and  most  expeditious  manner.  They  generally  begin  to 
slope  on  the  lower  side  of  one  or  more  blocks,  and  work  upward  along  the  con- 
tact. The  manner  of  sloping  varies  slightly  according  to  the  nature  of  the  body. 
If  the  ore  is  damp  and  soft,  like  the  ores  of  the  Forsaken  and  Old  Waterloo,  it  is 
picked  down  only.  When  the  ore  is  badly  mixed  with  waste,  picking  is  also  done 
as  much  as  possible.  Where  the  ore  is  hard,  or  where  it  is  quite  solid  but  un- 
mixed with  waste,  it  is  blasted  out.  The  highly  siliceous  ores  are  the  hardest  to 
stope,  as  they  are  very  hard  to  drill  and  often  break  with  a  short  fracture.  The 
thick  bodies  of  granular  carbonate  of  lead  are  also  blasted  down.  In  the  Upper 
Waterloo  the  holes  were  bored  in  this  ore  in  a  few  minutes  with  long  iron  augers, 
and  a  shot  put  in.  The  ore  was  thus  brought  down  much  faster  than  a  man  could 


64  EXTRACTING   THE  ORES. 

pick  it.  The  augers  were  used  instead  of  drills,  as  the  powder  made  by  the  drill 
packed  before  it  and  made  the  progress  very  slow,  while  with  the  auger  a  i-inch 
hole  2  feet  in  depth  could  be  bored  in  a  few  minutes.  As  the  ore  is  stoped  it  is 
separated  from  the  waste  as  much  as  possible  and  sent  up  to  the  bins,  where  it  is 
again  sorted  by  daylight.  As  much  of  the  waste  as  can  be  stowed  is  kept  down 
the  mine;  the  rest  is  sent  up  and  thrown  on  the  dump.  Anything  fit  for  dressing 
which  has  to  be  stoped  is  sent  up  for  the  third-class  dump. 

The  method  of  putting  in  the  slope-supports  is  very  simple  when  the  ore -body 
is  not  exceedingly  thick ;  that  is,  when  it  is  less  than  six  or  eight  feet  thick,  as 
are  most  of  the  bodies  of  the  Morning  Star  mine.  In  such  a  body  stulls  are  put 
in  for  temporary  support  as  the  work  progresses,  and  as  soon  as  there  is  room 
these  are  replaced  by  cribs  for  permanent  support.  The  waste  is  stowed  in  these 
cribs.  Where  the  body  is  much  thicker  and  stulls  cannot  be  used,  square  sets  or, 
much  more  commonly,  high  cribs  are  put  in  at  once.  The  way  these  are  put  in 
has  already  been  described. 

ASSAYING  THE  ORJES. — The  variety  of  the  ores,  their  differences  in  value,  and 
the  fact  that  many  of  the  products,  though  alike  in  all  other  respects,  are  some- 
times ore  and  sometimes  waste,  have  already  been  shown  in  the  former  chapters. 
Unless  the  percentage  of  lead  in  the  ore  is  very  high,  or  the  silver  is  visible  in  it 
as  the  chloride,  the  most  experienced  miner  cannot  depend  on  looks  alone  to  dis- 
tinguish it  from  waste.  The  only  trustworthy  way  of  distinguishing  the  ores  is 
by  assay.  The  importance  of  having  frequent  assays  made  to  tell  what  is  ore  and 
what  is  waste  cannot  be  overestimated.  The  old  Morning  Star  Company  did  not 
pursue  this  course,  and  as  a  consequence  passed  by  large  quantities  of  ore,  and, 
worse  than  this,  stowed  away  large  quantities  of  it  because  it  looked  like  waste, 
when  in  reality  it  would  at  that  time  have  paid  them  handsome  profits.  To  keep 
track  of  the  ores  each  mine  is  furnished  with  an  assay  office,  an  assayer  and  his 
assistant.  Every  "shift  boss"  is  required  to  collect  frequent  samples  from  wher- 
ever development  is  progressing  and  from  wherever  his  men  are  stoping,  so  that 
he  may  never  miss  any  ore.  If  there  is  any  doubt  about  the  value  of  any  material, 
even  when  the  quantity  would  not  exceed  a  ton,  an  assay  is  made  to  decide  upon 
it.  The  superintendent  and  time-keeper  also  sample  where  they  think  necessary, 
and  to  the  latter  officer  belongs  the  duty  of  recording  the  samples  and  distributing 
the  returns  of  the  assayer.  The  ore-sorters  also  send  in  doubtful  samples  to 
assist  them  in  sorting.  Consequently  there  is  little  danger  of  passing  over  an 
ore  or  of  mixing  it  with  much  waste.  By  a  few  assays  from  one  place  the  miner 
can  soon  learn  to  tell  ore  from  gangue  at  that  place. 

Each  assay  office  has,  on  an  average,  from  40  to  50  of  these  assays  a  day.  Of 
course  great  accuracy  is  not  required,  as  it  is  only  desired  to  distinguish  ore  from 
waste.  One  assay  of  each  sample  is  made.  Both  the  lead  and  silver  are  deter- 


SCALE  OF  PRICES.  65 

mined.  The  lead  assay  is  made  first,  and  if  the  button  shows  over  10  per  cent  of 
lead  it  is  cupelled  for  the  silver;  if  less  than  this,  a  scorification  is  made.  Where 
the  per  cent  of  lead  is  low  there  is  no  sulphur,  and  it  is  found  that  the  lead  collects 
almost  all  the  silver  when  there  is  not  much  of  the  latter  metal  present.  There  is 
considerable  loss  only  where  there  is  a  great  deal  of  silver,  and  in  such  a  case 
enough  can  always  be  collected  to  show  that  the  ore  will  pay.  The  best  furnace 
for  these  assays  is  the  soft-coal  furnace  with  two  muffles,  one  above  the  other. 
Such  a  furnace  when  hot  will  allow  seven  to  nine  crucibles  to  run  in  the  upper 
muffle,  while  twelve  scorifiers  run  in  the  lower.  The  heat  can  be  easily  regulated, 
and  the  same  furnace  is  excellently  adapted  for  control  assays. 


SELLING  THE  ORES. 

The  ores  are  not  treated  by  the  companies,  but  are  sold  to  the  various  smel- 
ters about  Leadville  and  to  Grant's  smelting  works  at  Denver.  The  Leadville 
smelting  works  are  situated  along  California  and  Big  Evans  Gulches,  where 
water  for  the  engines  and  furnaces  and  an  approach  for  the  railway,  as  well  as  fine 
positions  for  furnaces  and  ore- floors,  are  afforded.  The  ore  is  hauled  from  the 
shaft-houses  to  these  works  in  wagons.  This  is  done  by  a  contractor  who  agrees 
to  haul  all  the  ore  taken  out  at  a  certain  rate  per  ton  (from  $0.70  to  $1.00).  The 
two  mines  have  a  weigh-house,  and  all  the  ore  shipped  is  weighed  there  as  well  as 
at  the  smelters. 

The  ore  is  sold  in  lots  of  about  50  tons  each.  They  seldom  vary  5  tons  from  this 
amount.  Each  lot  is  sampled  at  the  smelting  works,  and  the  ore  is  sold  on  the 
assay  of  this  sample.  When  reduced  to  a  final  half-pint  the  sample  is  divided  into 
three  portions  and  sealed  up  in  bottles  or  paper  sacks.  One  of  these  goes  to  the 
mine  assayer  and  one  to  the  smelter.  The  third  is  kept  for  a  referee  in  case  of 
dispute.  Each  assayer  makes  three  scorification  assays  for  silver  and  duplicate 
assays  for  lead.  On  all  ordinary  lots  running  from  10  to  40  ounces  the  assayers  should 
agree  within  a  half-ounce.  Their  lead  assays  should  come  within  less  than  £  per 
cent  of  each  other.  When  the  assays  are  satisfactory  the  mean  between  the  two 
returns  is  taken  as  the  basis  on  which  the  ore  is  sold. 

SCALE  OF  PRICES.— It  is  highly  desirable  to  the  smelter  to  have  ores  rich  in 
lead  to  mix  with  those  poor  in  that  metal,  and  a  scale  of  prices  based  on  the 
amount  of  lead  in  the  ore  is  the  result.  Thus,  if  the  ore  contains  very  little  lead 
a  very  low  price  is  usually  paid  per  pound  for  it,  and  a  high  price  is  charged 
for  smelting.  If,  on  the  other  hand,  the  ore  contains  much  lead  a  higher  price 
per  pound  is  paid  for  it,  and  a  low  charge  is  made  for  smelting  it.  The  price 
paid  for  silver  is  always  six  cents  an  ounce  less  than  the  market  value,  whatever 


66  EXTRACTING    THE  ORES. 

the  richness  of  the  ore.  The  following  is  a  copy  of  an  ore  contract.  It  shows  the 
form  of  the  contract  and  the  scale  of  prices.  The  italics  occupy  blank  spaces  in 
the  printed  form  and  are  filled  in  when  the  contract  is  made. 

ORE   CONTRACT. 

THIS  AGREEMENT,  made  this  fifteenth  day  of  July,  1882,  between  The  Morning  Star  Consolidated  Mining 

Company,  party  of  the  first  part,  by  W.  S.  WARD,  General  Manager,  and 

Smelting  Co.,  party  of  the  second  part,  WITNESSETH  : 

1st.  That  said  Morning  Star  Consolidated  Mining  Company,  by  its  General  Manager  aforesaid,  in  con- 
sideration of  payments  hereafter  mentioned,  to  be  made  by  said  second  party  to  said  first  party,  has  agreed 
and  does  hereby  promise  and  agree  to  and  with  said  second  party  to  sell  and  deliver  at  the  works  of 
said  second  party  in  Leadville,  three  fourths  (})  of  the  output  of  said  Morning  Star  Consolidated  mine,  tons 
of  ore  from  its  mines,  the  delivery  thereof  to  begin  on  the  fifteenth  day  of  August,  1882,  and  to  continue 
(unavoidable  delays  and  accidents  excepted)  until  the  first  day  of  February,  1883.  And  the  amounts  de- 
livered each  day  (Sundays  excepted)  to  approximate  three  fourths  of  the  product  of  said  mine  for  each  day,  it 
being  the  intent  hereof  to  sell  and  deliver  to  said  second  party  only  three  fourths  of  product  of  said  mine 
during  the  time  which  will  be  required  to  produce  and  deliver  the  said  ore  hereby  agreed  to  be  sold  to  said 
second  party. 

2d.  In  consideration  of  the  foregoing,  the  said Smelting  Co.,  party  of  the 

second  part,  agree*  to  pay  for  the  said  ore,  to  the  said  first  party,  at  the  following  rates  : 

For  Silver,  New  York  quotation  at  time  of  settlement,  less  six  (6)  cents  per  ounce. 

FOR  ORE  CONTAINING: 

Up  to  and  including  20  per  cent  Lead 25  cents  per  unit,*  less  $16  per  ton 

Over  20      "                 "  25  "  "  25  "  "  15  " 

"    25       "                 "  30  "  "  30  "  "  14  " 

"    30       "                 "  35  "  "  SO  "  "  13  " 

-    35       "                •"  40  "  "  35  "  "  12  " 

"    40       "                 "  45  "  "  40  "  rt  //  " 

"    45       "                 "  50  "  "  40  "  "  11 

"    50       "                 "  55  "  "  42  "  "  10  " 

"    55       "                 "  60  "  "  45  "  "  10  " 

••    60      "                 "  65  "  "  50  "  "  10  " 

"    65       "                 "  ..  "  "  50  "  "  9  " 

All  Gold  over  one  half  ounce  per  ton  to  be  paid  for  at  the  rate  of  twenty  dollars  ($20.)  per  ounce  for  entire 
gold  contents. 

All  assays,  whether  Gold,  Silver  or  Lead,  to  be  reported  to  the  tenth  of  the  unit. 

All  expenses  of  hauling  in  excess  seventy  cents  per  ton  to  be  paid  by  said  party  of  the  second  part,  and 
all  payments  to  be  made  in  lawful  money,  upon  request  of  said  first  party,  whenever  fifty  tons  or  less  shall 
have  been  delivered,  sampled  and  assayed. 

AH  ores  shall  be  sampled  and  assayed  without  unnecessary  delay,  and  in  case  of  disagreement  as  to 
values,  as  shown  by  the  assays  of  the  respective  parties  hereto,  the  umpire  or  third  sample,  shall  be  referred 

to for  assay,  and  his  determination  of  the  value  from  such  sample  shall  be 

final,  and  fix  the  value  of  said  ores  so  sampled,  which  values  so  fixed  shall  thereupon  be  paid  for  said  ores 
by  said  second  party  to  said  first  party,  and  the  expense  incurred  for  said  umpire  assay  to  be  paid  for  by 
losing  party.  Moisture  determinations  to  be  made  incase  of  dispute  on  the  water-bath. 

It  is  understood  and  agreed  that  if  for  any  reasonable  cause  the  said  first  party  should  be  unable  to 
produce  the  amount  of  ore  herein  contracted  to  be  sold,  then,  as  to  such  part  not  produced,  this  contract 
shall  be  void. 


Signed  j 


*The  unit  is  one  per  cent  of  a  ton;  that  is,  20  pounds. 


VALUE  OF   THE  ORES. 


67 


Since  February  i,  1883,  the  following  very  advantageous  terms  have  been 
made  by  both  mines  with  one  of  the  smelting  companies :  For  silver,  6  cents 
an  ounce  less  than  the  New  York  quotation  at  the  time  of  settlement.  For 
lead,  45  cents  per  unit  when  the  New  York  price  is  above  5  cents  per  pound, 
40  per  unit  when  it  is  between  4^  and  5  cents,  and  35  cents  per  unit  when  it  is 
below  4^  cents  per  pound.  From  this  value  thus  obtained  the  smelter  deducts  $9 
a  ton  as  a  charge  for  treatment. 

VALUE  OF  THE  ORES. — The  ore-books,  recording  the  ore-sales,  do  not  state  the 
amounts  of  silver  and  lead  in  the  ores,  though  they  give  all  the  data  for  obtaining 
them.  To  obtain  these,  tedious  calculations  have  to  be  made  for  each  lot.  To 
give  a  general  idea  of  the  average  richness  of  the  ores  of  the  two  mines  the  follow- 
ing table  was  prepared.  It  shows  the  number  of  net  tons  of  ore  shipped  from 
each  mine,  and  the  silver  and  lead  in  them,  for  each  of  the  three  months,  August, 
September  and  October,  1882  : 

TABLE  SHOWING  PRODUCTION  OF  EVENING  STAR. 


Net  Tons. 

Oz.  Ag. 

Tons  Lead. 

Av.  Oz. 
per  ton. 

Per  cent  Pb. 
per  ton. 

2,828.089 

115,725.3 

574.589 

40.92 

20.31 

2  228.  ^m 

88  278.2 

302.636 

39.65 

13.58 

1,258.871 

46,117.4 

140.215 

36.63 

11.14 

Total  

5,315.475 

250,120  9 

1,017.440 

TABLE  SHOWING  PRODUCTION  OF  MORNING  STAR. 


Net  Tons. 

Oz.  Ag. 

Tons  Lead. 

Av.  Oz. 
per  ton. 

Per  cent  Pb. 
per  ton. 

1,749.029 

43,014.0 

678.848 

24-53 

38.8 

September  

1,070.921 

23.753.4 

473-057 

22.27 

44-2 

1,975  006 

52.238.0 

691.968 

26.45 

35-o 

Total  

4,794.956 

119,005.4 

1,843.873 

These  tables  show  prominently  the  high  average  of  the  Morning  Star  ores  in 
lead.  The  Evening  Star  ores  never  averaged  as  high  as  the  former  in  this  metal, 
but  are  lower  in  lead  for  the  three  months  given  than  they  were  before  the  large 
body  was  stoped.  The  fact  that  the  Evening  Star  ores  are  much  richer  in  silver 
than  those  of  the  Morning  Star  is  also  prominently  brought  out.  The  variations  in 
value  of  the  various  lots  is,  comparatively  speaking,  small.  Thus  in  the  Morning 
Star  sales  for  the  three  months  only  8  lots  out  of  the  98  went  over  40  ounces  per 
ton,  and  the  highest  was  46  ounces.  The  lowest  ran  8£  ounces,  with  4  lots  below 
10  ounces. 

In  lead  the  variation  was  great,  the  limits  being  65  per  cent  on  the  one  hand 


68  EXTRACTING   THE  ORES. 

and  14^  percent  on  the  other.    There  were  16  lots  below  25  per  cent,  18  lots  above 
50,  and  6  above  60  per  cent. 

The  Evening  Star  shows  no  greater  variations.  From  the  125  lots  sold,  8  went 
over  60  ounces,  with  a  maximum  of  75  ounces.  But  3  lots  ran  below  25  ounces, 
and  the  lowest  was  23^  ounces.  The  lead  was  always  very  low;  only  13  lots 
assayed  over  25  per  cent,  and  the  highest  was  but  31^.  Of  the  17  lots  which  ran 
below  10  per  cent  lead,  13  were  sold  during  the  month  of  October.  The  exceed- 
ingly low  minimum  was  6  per  cent,  the  lowest  of  any  shipment  of  either  mine 
noticed  on  the  books. 

In  order  to  show  the  expenses  of  mining  and  the  items  of  greatest  expense,  the 
following  table,  showing  the  expenditures  of  the  Evening  Star  mine  up  to  Oct.  i, 
1882,  is  given.  The  total  represents  the  amount  received  from  the  smelter  for  the 
ores.  The  value  of  the  silver  and  lead  produced  by  the  mine  would,  of  course,  be 
far  greater. 

TABLE.  • 

Cash  on  hand $4,82409 

Labor 386,059  01 

Improvement • 20,844  85 

Machinery 17,268  53 

Iron,  steel,  etc 33,603  81 

General  supplies  and  expenses 4,049  18 

General  transportation 272  86 

Assaying  materials 3,324  48 

Horse  feed 3,957  09 

Legal  service  and  surveys 3,293  99 

Office  expenses 1,568  18 

Ore  transportation 42, 333  1 1 

Timber 41,998  29 

Fuel 12,434  18 

Insurance 479  15 

Telegraph  and  telephone 723  97 

Leadville  Water  Co 1,894  25 

Tax 47762 

New  York  office  as  net  earnings 1,410,592  20 

Total  received  from  sale  of  ores $1,989,998  84 


THE   END. 


PL.  I 


SECTION    1. 


White 
Porphyry 


Gray 
Porpliyry 


GraiuJar 
Lead  ( ' :  i  rl><  1 1 1 ;  1 1 1  • 


Basic  Iron. 
Sulphate 


Jxaru.  Ore 


Blue 
Limestone 


3 

03 


— 

S3 

w 


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S3 


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4) 

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8 
53 


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I 

£ 


a 

u 


<0 

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a 


Pl.V. 


Fig. 2 


Fig.  3. 


PI. VI. 


Fig.l. 


Ffq.2. 


Fig.3, 


Fig.  4. 


Scale:  1+ 


